diff options
Diffstat (limited to 'kernel/fs/ntfs/attrib.c')
| -rw-r--r-- | kernel/fs/ntfs/attrib.c | 2614 |
1 files changed, 2614 insertions, 0 deletions
diff --git a/kernel/fs/ntfs/attrib.c b/kernel/fs/ntfs/attrib.c new file mode 100644 index 000000000..250ed5b20 --- /dev/null +++ b/kernel/fs/ntfs/attrib.c @@ -0,0 +1,2614 @@ +/** + * attrib.c - NTFS attribute operations. Part of the Linux-NTFS project. + * + * Copyright (c) 2001-2012 Anton Altaparmakov and Tuxera Inc. + * Copyright (c) 2002 Richard Russon + * + * This program/include file is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as published + * by the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program/include file is distributed in the hope that it will be + * useful, but WITHOUT ANY WARRANTY; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program (in the main directory of the Linux-NTFS + * distribution in the file COPYING); if not, write to the Free Software + * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/buffer_head.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/swap.h> +#include <linux/writeback.h> + +#include "attrib.h" +#include "debug.h" +#include "layout.h" +#include "lcnalloc.h" +#include "malloc.h" +#include "mft.h" +#include "ntfs.h" +#include "types.h" + +/** + * ntfs_map_runlist_nolock - map (a part of) a runlist of an ntfs inode + * @ni: ntfs inode for which to map (part of) a runlist + * @vcn: map runlist part containing this vcn + * @ctx: active attribute search context if present or NULL if not + * + * Map the part of a runlist containing the @vcn of the ntfs inode @ni. + * + * If @ctx is specified, it is an active search context of @ni and its base mft + * record. This is needed when ntfs_map_runlist_nolock() encounters unmapped + * runlist fragments and allows their mapping. If you do not have the mft + * record mapped, you can specify @ctx as NULL and ntfs_map_runlist_nolock() + * will perform the necessary mapping and unmapping. + * + * Note, ntfs_map_runlist_nolock() saves the state of @ctx on entry and + * restores it before returning. Thus, @ctx will be left pointing to the same + * attribute on return as on entry. However, the actual pointers in @ctx may + * point to different memory locations on return, so you must remember to reset + * any cached pointers from the @ctx, i.e. after the call to + * ntfs_map_runlist_nolock(), you will probably want to do: + * m = ctx->mrec; + * a = ctx->attr; + * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that + * you cache ctx->mrec in a variable @m of type MFT_RECORD *. + * + * Return 0 on success and -errno on error. There is one special error code + * which is not an error as such. This is -ENOENT. It means that @vcn is out + * of bounds of the runlist. + * + * Note the runlist can be NULL after this function returns if @vcn is zero and + * the attribute has zero allocated size, i.e. there simply is no runlist. + * + * WARNING: If @ctx is supplied, regardless of whether success or failure is + * returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx + * is no longer valid, i.e. you need to either call + * ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it. + * In that case PTR_ERR(@ctx->mrec) will give you the error code for + * why the mapping of the old inode failed. + * + * Locking: - The runlist described by @ni must be locked for writing on entry + * and is locked on return. Note the runlist will be modified. + * - If @ctx is NULL, the base mft record of @ni must not be mapped on + * entry and it will be left unmapped on return. + * - If @ctx is not NULL, the base mft record must be mapped on entry + * and it will be left mapped on return. + */ +int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn, ntfs_attr_search_ctx *ctx) +{ + VCN end_vcn; + unsigned long flags; + ntfs_inode *base_ni; + MFT_RECORD *m; + ATTR_RECORD *a; + runlist_element *rl; + struct page *put_this_page = NULL; + int err = 0; + bool ctx_is_temporary, ctx_needs_reset; + ntfs_attr_search_ctx old_ctx = { NULL, }; + + ntfs_debug("Mapping runlist part containing vcn 0x%llx.", + (unsigned long long)vcn); + if (!NInoAttr(ni)) + base_ni = ni; + else + base_ni = ni->ext.base_ntfs_ino; + if (!ctx) { + ctx_is_temporary = ctx_needs_reset = true; + m = map_mft_record(base_ni); + if (IS_ERR(m)) + return PTR_ERR(m); + ctx = ntfs_attr_get_search_ctx(base_ni, m); + if (unlikely(!ctx)) { + err = -ENOMEM; + goto err_out; + } + } else { + VCN allocated_size_vcn; + + BUG_ON(IS_ERR(ctx->mrec)); + a = ctx->attr; + BUG_ON(!a->non_resident); + ctx_is_temporary = false; + end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn); + read_lock_irqsave(&ni->size_lock, flags); + allocated_size_vcn = ni->allocated_size >> + ni->vol->cluster_size_bits; + read_unlock_irqrestore(&ni->size_lock, flags); + if (!a->data.non_resident.lowest_vcn && end_vcn <= 0) + end_vcn = allocated_size_vcn - 1; + /* + * If we already have the attribute extent containing @vcn in + * @ctx, no need to look it up again. We slightly cheat in + * that if vcn exceeds the allocated size, we will refuse to + * map the runlist below, so there is definitely no need to get + * the right attribute extent. + */ + if (vcn >= allocated_size_vcn || (a->type == ni->type && + a->name_length == ni->name_len && + !memcmp((u8*)a + le16_to_cpu(a->name_offset), + ni->name, ni->name_len) && + sle64_to_cpu(a->data.non_resident.lowest_vcn) + <= vcn && end_vcn >= vcn)) + ctx_needs_reset = false; + else { + /* Save the old search context. */ + old_ctx = *ctx; + /* + * If the currently mapped (extent) inode is not the + * base inode we will unmap it when we reinitialize the + * search context which means we need to get a + * reference to the page containing the mapped mft + * record so we do not accidentally drop changes to the + * mft record when it has not been marked dirty yet. + */ + if (old_ctx.base_ntfs_ino && old_ctx.ntfs_ino != + old_ctx.base_ntfs_ino) { + put_this_page = old_ctx.ntfs_ino->page; + page_cache_get(put_this_page); + } + /* + * Reinitialize the search context so we can lookup the + * needed attribute extent. + */ + ntfs_attr_reinit_search_ctx(ctx); + ctx_needs_reset = true; + } + } + if (ctx_needs_reset) { + err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len, + CASE_SENSITIVE, vcn, NULL, 0, ctx); + if (unlikely(err)) { + if (err == -ENOENT) + err = -EIO; + goto err_out; + } + BUG_ON(!ctx->attr->non_resident); + } + a = ctx->attr; + /* + * Only decompress the mapping pairs if @vcn is inside it. Otherwise + * we get into problems when we try to map an out of bounds vcn because + * we then try to map the already mapped runlist fragment and + * ntfs_mapping_pairs_decompress() fails. + */ + end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn) + 1; + if (unlikely(vcn && vcn >= end_vcn)) { + err = -ENOENT; + goto err_out; + } + rl = ntfs_mapping_pairs_decompress(ni->vol, a, ni->runlist.rl); + if (IS_ERR(rl)) + err = PTR_ERR(rl); + else + ni->runlist.rl = rl; +err_out: + if (ctx_is_temporary) { + if (likely(ctx)) + ntfs_attr_put_search_ctx(ctx); + unmap_mft_record(base_ni); + } else if (ctx_needs_reset) { + /* + * If there is no attribute list, restoring the search context + * is accomplished simply by copying the saved context back over + * the caller supplied context. If there is an attribute list, + * things are more complicated as we need to deal with mapping + * of mft records and resulting potential changes in pointers. + */ + if (NInoAttrList(base_ni)) { + /* + * If the currently mapped (extent) inode is not the + * one we had before, we need to unmap it and map the + * old one. + */ + if (ctx->ntfs_ino != old_ctx.ntfs_ino) { + /* + * If the currently mapped inode is not the + * base inode, unmap it. + */ + if (ctx->base_ntfs_ino && ctx->ntfs_ino != + ctx->base_ntfs_ino) { + unmap_extent_mft_record(ctx->ntfs_ino); + ctx->mrec = ctx->base_mrec; + BUG_ON(!ctx->mrec); + } + /* + * If the old mapped inode is not the base + * inode, map it. + */ + if (old_ctx.base_ntfs_ino && + old_ctx.ntfs_ino != + old_ctx.base_ntfs_ino) { +retry_map: + ctx->mrec = map_mft_record( + old_ctx.ntfs_ino); + /* + * Something bad has happened. If out + * of memory retry till it succeeds. + * Any other errors are fatal and we + * return the error code in ctx->mrec. + * Let the caller deal with it... We + * just need to fudge things so the + * caller can reinit and/or put the + * search context safely. + */ + if (IS_ERR(ctx->mrec)) { + if (PTR_ERR(ctx->mrec) == + -ENOMEM) { + schedule(); + goto retry_map; + } else + old_ctx.ntfs_ino = + old_ctx. + base_ntfs_ino; + } + } + } + /* Update the changed pointers in the saved context. */ + if (ctx->mrec != old_ctx.mrec) { + if (!IS_ERR(ctx->mrec)) + old_ctx.attr = (ATTR_RECORD*)( + (u8*)ctx->mrec + + ((u8*)old_ctx.attr - + (u8*)old_ctx.mrec)); + old_ctx.mrec = ctx->mrec; + } + } + /* Restore the search context to the saved one. */ + *ctx = old_ctx; + /* + * We drop the reference on the page we took earlier. In the + * case that IS_ERR(ctx->mrec) is true this means we might lose + * some changes to the mft record that had been made between + * the last time it was marked dirty/written out and now. This + * at this stage is not a problem as the mapping error is fatal + * enough that the mft record cannot be written out anyway and + * the caller is very likely to shutdown the whole inode + * immediately and mark the volume dirty for chkdsk to pick up + * the pieces anyway. + */ + if (put_this_page) + page_cache_release(put_this_page); + } + return err; +} + +/** + * ntfs_map_runlist - map (a part of) a runlist of an ntfs inode + * @ni: ntfs inode for which to map (part of) a runlist + * @vcn: map runlist part containing this vcn + * + * Map the part of a runlist containing the @vcn of the ntfs inode @ni. + * + * Return 0 on success and -errno on error. There is one special error code + * which is not an error as such. This is -ENOENT. It means that @vcn is out + * of bounds of the runlist. + * + * Locking: - The runlist must be unlocked on entry and is unlocked on return. + * - This function takes the runlist lock for writing and may modify + * the runlist. + */ +int ntfs_map_runlist(ntfs_inode *ni, VCN vcn) +{ + int err = 0; + + down_write(&ni->runlist.lock); + /* Make sure someone else didn't do the work while we were sleeping. */ + if (likely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) <= + LCN_RL_NOT_MAPPED)) + err = ntfs_map_runlist_nolock(ni, vcn, NULL); + up_write(&ni->runlist.lock); + return err; +} + +/** + * ntfs_attr_vcn_to_lcn_nolock - convert a vcn into a lcn given an ntfs inode + * @ni: ntfs inode of the attribute whose runlist to search + * @vcn: vcn to convert + * @write_locked: true if the runlist is locked for writing + * + * Find the virtual cluster number @vcn in the runlist of the ntfs attribute + * described by the ntfs inode @ni and return the corresponding logical cluster + * number (lcn). + * + * If the @vcn is not mapped yet, the attempt is made to map the attribute + * extent containing the @vcn and the vcn to lcn conversion is retried. + * + * If @write_locked is true the caller has locked the runlist for writing and + * if false for reading. + * + * Since lcns must be >= 0, we use negative return codes with special meaning: + * + * Return code Meaning / Description + * ========================================== + * LCN_HOLE Hole / not allocated on disk. + * LCN_ENOENT There is no such vcn in the runlist, i.e. @vcn is out of bounds. + * LCN_ENOMEM Not enough memory to map runlist. + * LCN_EIO Critical error (runlist/file is corrupt, i/o error, etc). + * + * Locking: - The runlist must be locked on entry and is left locked on return. + * - If @write_locked is 'false', i.e. the runlist is locked for reading, + * the lock may be dropped inside the function so you cannot rely on + * the runlist still being the same when this function returns. + */ +LCN ntfs_attr_vcn_to_lcn_nolock(ntfs_inode *ni, const VCN vcn, + const bool write_locked) +{ + LCN lcn; + unsigned long flags; + bool is_retry = false; + + BUG_ON(!ni); + ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, %s_locked.", + ni->mft_no, (unsigned long long)vcn, + write_locked ? "write" : "read"); + BUG_ON(!NInoNonResident(ni)); + BUG_ON(vcn < 0); + if (!ni->runlist.rl) { + read_lock_irqsave(&ni->size_lock, flags); + if (!ni->allocated_size) { + read_unlock_irqrestore(&ni->size_lock, flags); + return LCN_ENOENT; + } + read_unlock_irqrestore(&ni->size_lock, flags); + } +retry_remap: + /* Convert vcn to lcn. If that fails map the runlist and retry once. */ + lcn = ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn); + if (likely(lcn >= LCN_HOLE)) { + ntfs_debug("Done, lcn 0x%llx.", (long long)lcn); + return lcn; + } + if (lcn != LCN_RL_NOT_MAPPED) { + if (lcn != LCN_ENOENT) + lcn = LCN_EIO; + } else if (!is_retry) { + int err; + + if (!write_locked) { + up_read(&ni->runlist.lock); + down_write(&ni->runlist.lock); + if (unlikely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) != + LCN_RL_NOT_MAPPED)) { + up_write(&ni->runlist.lock); + down_read(&ni->runlist.lock); + goto retry_remap; + } + } + err = ntfs_map_runlist_nolock(ni, vcn, NULL); + if (!write_locked) { + up_write(&ni->runlist.lock); + down_read(&ni->runlist.lock); + } + if (likely(!err)) { + is_retry = true; + goto retry_remap; + } + if (err == -ENOENT) + lcn = LCN_ENOENT; + else if (err == -ENOMEM) + lcn = LCN_ENOMEM; + else + lcn = LCN_EIO; + } + if (lcn != LCN_ENOENT) + ntfs_error(ni->vol->sb, "Failed with error code %lli.", + (long long)lcn); + return lcn; +} + +/** + * ntfs_attr_find_vcn_nolock - find a vcn in the runlist of an ntfs inode + * @ni: ntfs inode describing the runlist to search + * @vcn: vcn to find + * @ctx: active attribute search context if present or NULL if not + * + * Find the virtual cluster number @vcn in the runlist described by the ntfs + * inode @ni and return the address of the runlist element containing the @vcn. + * + * If the @vcn is not mapped yet, the attempt is made to map the attribute + * extent containing the @vcn and the vcn to lcn conversion is retried. + * + * If @ctx is specified, it is an active search context of @ni and its base mft + * record. This is needed when ntfs_attr_find_vcn_nolock() encounters unmapped + * runlist fragments and allows their mapping. If you do not have the mft + * record mapped, you can specify @ctx as NULL and ntfs_attr_find_vcn_nolock() + * will perform the necessary mapping and unmapping. + * + * Note, ntfs_attr_find_vcn_nolock() saves the state of @ctx on entry and + * restores it before returning. Thus, @ctx will be left pointing to the same + * attribute on return as on entry. However, the actual pointers in @ctx may + * point to different memory locations on return, so you must remember to reset + * any cached pointers from the @ctx, i.e. after the call to + * ntfs_attr_find_vcn_nolock(), you will probably want to do: + * m = ctx->mrec; + * a = ctx->attr; + * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that + * you cache ctx->mrec in a variable @m of type MFT_RECORD *. + * Note you need to distinguish between the lcn of the returned runlist element + * being >= 0 and LCN_HOLE. In the later case you have to return zeroes on + * read and allocate clusters on write. + * + * Return the runlist element containing the @vcn on success and + * ERR_PTR(-errno) on error. You need to test the return value with IS_ERR() + * to decide if the return is success or failure and PTR_ERR() to get to the + * error code if IS_ERR() is true. + * + * The possible error return codes are: + * -ENOENT - No such vcn in the runlist, i.e. @vcn is out of bounds. + * -ENOMEM - Not enough memory to map runlist. + * -EIO - Critical error (runlist/file is corrupt, i/o error, etc). + * + * WARNING: If @ctx is supplied, regardless of whether success or failure is + * returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx + * is no longer valid, i.e. you need to either call + * ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it. + * In that case PTR_ERR(@ctx->mrec) will give you the error code for + * why the mapping of the old inode failed. + * + * Locking: - The runlist described by @ni must be locked for writing on entry + * and is locked on return. Note the runlist may be modified when + * needed runlist fragments need to be mapped. + * - If @ctx is NULL, the base mft record of @ni must not be mapped on + * entry and it will be left unmapped on return. + * - If @ctx is not NULL, the base mft record must be mapped on entry + * and it will be left mapped on return. + */ +runlist_element *ntfs_attr_find_vcn_nolock(ntfs_inode *ni, const VCN vcn, + ntfs_attr_search_ctx *ctx) +{ + unsigned long flags; + runlist_element *rl; + int err = 0; + bool is_retry = false; + + BUG_ON(!ni); + ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, with%s ctx.", + ni->mft_no, (unsigned long long)vcn, ctx ? "" : "out"); + BUG_ON(!NInoNonResident(ni)); + BUG_ON(vcn < 0); + if (!ni->runlist.rl) { + read_lock_irqsave(&ni->size_lock, flags); + if (!ni->allocated_size) { + read_unlock_irqrestore(&ni->size_lock, flags); + return ERR_PTR(-ENOENT); + } + read_unlock_irqrestore(&ni->size_lock, flags); + } +retry_remap: + rl = ni->runlist.rl; + if (likely(rl && vcn >= rl[0].vcn)) { + while (likely(rl->length)) { + if (unlikely(vcn < rl[1].vcn)) { + if (likely(rl->lcn >= LCN_HOLE)) { + ntfs_debug("Done."); + return rl; + } + break; + } + rl++; + } + if (likely(rl->lcn != LCN_RL_NOT_MAPPED)) { + if (likely(rl->lcn == LCN_ENOENT)) + err = -ENOENT; + else + err = -EIO; + } + } + if (!err && !is_retry) { + /* + * If the search context is invalid we cannot map the unmapped + * region. + */ + if (IS_ERR(ctx->mrec)) + err = PTR_ERR(ctx->mrec); + else { + /* + * The @vcn is in an unmapped region, map the runlist + * and retry. + */ + err = ntfs_map_runlist_nolock(ni, vcn, ctx); + if (likely(!err)) { + is_retry = true; + goto retry_remap; + } + } + if (err == -EINVAL) + err = -EIO; + } else if (!err) + err = -EIO; + if (err != -ENOENT) + ntfs_error(ni->vol->sb, "Failed with error code %i.", err); + return ERR_PTR(err); +} + +/** + * ntfs_attr_find - find (next) attribute in mft record + * @type: attribute type to find + * @name: attribute name to find (optional, i.e. NULL means don't care) + * @name_len: attribute name length (only needed if @name present) + * @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present) + * @val: attribute value to find (optional, resident attributes only) + * @val_len: attribute value length + * @ctx: search context with mft record and attribute to search from + * + * You should not need to call this function directly. Use ntfs_attr_lookup() + * instead. + * + * ntfs_attr_find() takes a search context @ctx as parameter and searches the + * mft record specified by @ctx->mrec, beginning at @ctx->attr, for an + * attribute of @type, optionally @name and @val. + * + * If the attribute is found, ntfs_attr_find() returns 0 and @ctx->attr will + * point to the found attribute. + * + * If the attribute is not found, ntfs_attr_find() returns -ENOENT and + * @ctx->attr will point to the attribute before which the attribute being + * searched for would need to be inserted if such an action were to be desired. + * + * On actual error, ntfs_attr_find() returns -EIO. In this case @ctx->attr is + * undefined and in particular do not rely on it not changing. + * + * If @ctx->is_first is 'true', the search begins with @ctx->attr itself. If it + * is 'false', the search begins after @ctx->attr. + * + * If @ic is IGNORE_CASE, the @name comparisson is not case sensitive and + * @ctx->ntfs_ino must be set to the ntfs inode to which the mft record + * @ctx->mrec belongs. This is so we can get at the ntfs volume and hence at + * the upcase table. If @ic is CASE_SENSITIVE, the comparison is case + * sensitive. When @name is present, @name_len is the @name length in Unicode + * characters. + * + * If @name is not present (NULL), we assume that the unnamed attribute is + * being searched for. + * + * Finally, the resident attribute value @val is looked for, if present. If + * @val is not present (NULL), @val_len is ignored. + * + * ntfs_attr_find() only searches the specified mft record and it ignores the + * presence of an attribute list attribute (unless it is the one being searched + * for, obviously). If you need to take attribute lists into consideration, + * use ntfs_attr_lookup() instead (see below). This also means that you cannot + * use ntfs_attr_find() to search for extent records of non-resident + * attributes, as extents with lowest_vcn != 0 are usually described by the + * attribute list attribute only. - Note that it is possible that the first + * extent is only in the attribute list while the last extent is in the base + * mft record, so do not rely on being able to find the first extent in the + * base mft record. + * + * Warning: Never use @val when looking for attribute types which can be + * non-resident as this most likely will result in a crash! + */ +static int ntfs_attr_find(const ATTR_TYPE type, const ntfschar *name, + const u32 name_len, const IGNORE_CASE_BOOL ic, + const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx) +{ + ATTR_RECORD *a; + ntfs_volume *vol = ctx->ntfs_ino->vol; + ntfschar *upcase = vol->upcase; + u32 upcase_len = vol->upcase_len; + + /* + * Iterate over attributes in mft record starting at @ctx->attr, or the + * attribute following that, if @ctx->is_first is 'true'. + */ + if (ctx->is_first) { + a = ctx->attr; + ctx->is_first = false; + } else + a = (ATTR_RECORD*)((u8*)ctx->attr + + le32_to_cpu(ctx->attr->length)); + for (;; a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))) { + if ((u8*)a < (u8*)ctx->mrec || (u8*)a > (u8*)ctx->mrec + + le32_to_cpu(ctx->mrec->bytes_allocated)) + break; + ctx->attr = a; + if (unlikely(le32_to_cpu(a->type) > le32_to_cpu(type) || + a->type == AT_END)) + return -ENOENT; + if (unlikely(!a->length)) + break; + if (a->type != type) + continue; + /* + * If @name is present, compare the two names. If @name is + * missing, assume we want an unnamed attribute. + */ + if (!name) { + /* The search failed if the found attribute is named. */ + if (a->name_length) + return -ENOENT; + } else if (!ntfs_are_names_equal(name, name_len, + (ntfschar*)((u8*)a + le16_to_cpu(a->name_offset)), + a->name_length, ic, upcase, upcase_len)) { + register int rc; + + rc = ntfs_collate_names(name, name_len, + (ntfschar*)((u8*)a + + le16_to_cpu(a->name_offset)), + a->name_length, 1, IGNORE_CASE, + upcase, upcase_len); + /* + * If @name collates before a->name, there is no + * matching attribute. + */ + if (rc == -1) + return -ENOENT; + /* If the strings are not equal, continue search. */ + if (rc) + continue; + rc = ntfs_collate_names(name, name_len, + (ntfschar*)((u8*)a + + le16_to_cpu(a->name_offset)), + a->name_length, 1, CASE_SENSITIVE, + upcase, upcase_len); + if (rc == -1) + return -ENOENT; + if (rc) + continue; + } + /* + * The names match or @name not present and attribute is + * unnamed. If no @val specified, we have found the attribute + * and are done. + */ + if (!val) + return 0; + /* @val is present; compare values. */ + else { + register int rc; + + rc = memcmp(val, (u8*)a + le16_to_cpu( + a->data.resident.value_offset), + min_t(u32, val_len, le32_to_cpu( + a->data.resident.value_length))); + /* + * If @val collates before the current attribute's + * value, there is no matching attribute. + */ + if (!rc) { + register u32 avl; + + avl = le32_to_cpu( + a->data.resident.value_length); + if (val_len == avl) + return 0; + if (val_len < avl) + return -ENOENT; + } else if (rc < 0) + return -ENOENT; + } + } + ntfs_error(vol->sb, "Inode is corrupt. Run chkdsk."); + NVolSetErrors(vol); + return -EIO; +} + +/** + * load_attribute_list - load an attribute list into memory + * @vol: ntfs volume from which to read + * @runlist: runlist of the attribute list + * @al_start: destination buffer + * @size: size of the destination buffer in bytes + * @initialized_size: initialized size of the attribute list + * + * Walk the runlist @runlist and load all clusters from it copying them into + * the linear buffer @al. The maximum number of bytes copied to @al is @size + * bytes. Note, @size does not need to be a multiple of the cluster size. If + * @initialized_size is less than @size, the region in @al between + * @initialized_size and @size will be zeroed and not read from disk. + * + * Return 0 on success or -errno on error. + */ +int load_attribute_list(ntfs_volume *vol, runlist *runlist, u8 *al_start, + const s64 size, const s64 initialized_size) +{ + LCN lcn; + u8 *al = al_start; + u8 *al_end = al + initialized_size; + runlist_element *rl; + struct buffer_head *bh; + struct super_block *sb; + unsigned long block_size; + unsigned long block, max_block; + int err = 0; + unsigned char block_size_bits; + + ntfs_debug("Entering."); + if (!vol || !runlist || !al || size <= 0 || initialized_size < 0 || + initialized_size > size) + return -EINVAL; + if (!initialized_size) { + memset(al, 0, size); + return 0; + } + sb = vol->sb; + block_size = sb->s_blocksize; + block_size_bits = sb->s_blocksize_bits; + down_read(&runlist->lock); + rl = runlist->rl; + if (!rl) { + ntfs_error(sb, "Cannot read attribute list since runlist is " + "missing."); + goto err_out; + } + /* Read all clusters specified by the runlist one run at a time. */ + while (rl->length) { + lcn = ntfs_rl_vcn_to_lcn(rl, rl->vcn); + ntfs_debug("Reading vcn = 0x%llx, lcn = 0x%llx.", + (unsigned long long)rl->vcn, + (unsigned long long)lcn); + /* The attribute list cannot be sparse. */ + if (lcn < 0) { + ntfs_error(sb, "ntfs_rl_vcn_to_lcn() failed. Cannot " + "read attribute list."); + goto err_out; + } + block = lcn << vol->cluster_size_bits >> block_size_bits; + /* Read the run from device in chunks of block_size bytes. */ + max_block = block + (rl->length << vol->cluster_size_bits >> + block_size_bits); + ntfs_debug("max_block = 0x%lx.", max_block); + do { + ntfs_debug("Reading block = 0x%lx.", block); + bh = sb_bread(sb, block); + if (!bh) { + ntfs_error(sb, "sb_bread() failed. Cannot " + "read attribute list."); + goto err_out; + } + if (al + block_size >= al_end) + goto do_final; + memcpy(al, bh->b_data, block_size); + brelse(bh); + al += block_size; + } while (++block < max_block); + rl++; + } + if (initialized_size < size) { +initialize: + memset(al_start + initialized_size, 0, size - initialized_size); + } +done: + up_read(&runlist->lock); + return err; +do_final: + if (al < al_end) { + /* + * Partial block. + * + * Note: The attribute list can be smaller than its allocation + * by multiple clusters. This has been encountered by at least + * two people running Windows XP, thus we cannot do any + * truncation sanity checking here. (AIA) + */ + memcpy(al, bh->b_data, al_end - al); + brelse(bh); + if (initialized_size < size) + goto initialize; + goto done; + } + brelse(bh); + /* Real overflow! */ + ntfs_error(sb, "Attribute list buffer overflow. Read attribute list " + "is truncated."); +err_out: + err = -EIO; + goto done; +} + +/** + * ntfs_external_attr_find - find an attribute in the attribute list of an inode + * @type: attribute type to find + * @name: attribute name to find (optional, i.e. NULL means don't care) + * @name_len: attribute name length (only needed if @name present) + * @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present) + * @lowest_vcn: lowest vcn to find (optional, non-resident attributes only) + * @val: attribute value to find (optional, resident attributes only) + * @val_len: attribute value length + * @ctx: search context with mft record and attribute to search from + * + * You should not need to call this function directly. Use ntfs_attr_lookup() + * instead. + * + * Find an attribute by searching the attribute list for the corresponding + * attribute list entry. Having found the entry, map the mft record if the + * attribute is in a different mft record/inode, ntfs_attr_find() the attribute + * in there and return it. + * + * On first search @ctx->ntfs_ino must be the base mft record and @ctx must + * have been obtained from a call to ntfs_attr_get_search_ctx(). On subsequent + * calls @ctx->ntfs_ino can be any extent inode, too (@ctx->base_ntfs_ino is + * then the base inode). + * + * After finishing with the attribute/mft record you need to call + * ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any + * mapped inodes, etc). + * + * If the attribute is found, ntfs_external_attr_find() returns 0 and + * @ctx->attr will point to the found attribute. @ctx->mrec will point to the + * mft record in which @ctx->attr is located and @ctx->al_entry will point to + * the attribute list entry for the attribute. + * + * If the attribute is not found, ntfs_external_attr_find() returns -ENOENT and + * @ctx->attr will point to the attribute in the base mft record before which + * the attribute being searched for would need to be inserted if such an action + * were to be desired. @ctx->mrec will point to the mft record in which + * @ctx->attr is located and @ctx->al_entry will point to the attribute list + * entry of the attribute before which the attribute being searched for would + * need to be inserted if such an action were to be desired. + * + * Thus to insert the not found attribute, one wants to add the attribute to + * @ctx->mrec (the base mft record) and if there is not enough space, the + * attribute should be placed in a newly allocated extent mft record. The + * attribute list entry for the inserted attribute should be inserted in the + * attribute list attribute at @ctx->al_entry. + * + * On actual error, ntfs_external_attr_find() returns -EIO. In this case + * @ctx->attr is undefined and in particular do not rely on it not changing. + */ +static int ntfs_external_attr_find(const ATTR_TYPE type, + const ntfschar *name, const u32 name_len, + const IGNORE_CASE_BOOL ic, const VCN lowest_vcn, + const u8 *val, const u32 val_len, ntfs_attr_search_ctx *ctx) +{ + ntfs_inode *base_ni, *ni; + ntfs_volume *vol; + ATTR_LIST_ENTRY *al_entry, *next_al_entry; + u8 *al_start, *al_end; + ATTR_RECORD *a; + ntfschar *al_name; + u32 al_name_len; + int err = 0; + static const char *es = " Unmount and run chkdsk."; + + ni = ctx->ntfs_ino; + base_ni = ctx->base_ntfs_ino; + ntfs_debug("Entering for inode 0x%lx, type 0x%x.", ni->mft_no, type); + if (!base_ni) { + /* First call happens with the base mft record. */ + base_ni = ctx->base_ntfs_ino = ctx->ntfs_ino; + ctx->base_mrec = ctx->mrec; + } + if (ni == base_ni) + ctx->base_attr = ctx->attr; + if (type == AT_END) + goto not_found; + vol = base_ni->vol; + al_start = base_ni->attr_list; + al_end = al_start + base_ni->attr_list_size; + if (!ctx->al_entry) + ctx->al_entry = (ATTR_LIST_ENTRY*)al_start; + /* + * Iterate over entries in attribute list starting at @ctx->al_entry, + * or the entry following that, if @ctx->is_first is 'true'. + */ + if (ctx->is_first) { + al_entry = ctx->al_entry; + ctx->is_first = false; + } else + al_entry = (ATTR_LIST_ENTRY*)((u8*)ctx->al_entry + + le16_to_cpu(ctx->al_entry->length)); + for (;; al_entry = next_al_entry) { + /* Out of bounds check. */ + if ((u8*)al_entry < base_ni->attr_list || + (u8*)al_entry > al_end) + break; /* Inode is corrupt. */ + ctx->al_entry = al_entry; + /* Catch the end of the attribute list. */ + if ((u8*)al_entry == al_end) + goto not_found; + if (!al_entry->length) + break; + if ((u8*)al_entry + 6 > al_end || (u8*)al_entry + + le16_to_cpu(al_entry->length) > al_end) + break; + next_al_entry = (ATTR_LIST_ENTRY*)((u8*)al_entry + + le16_to_cpu(al_entry->length)); + if (le32_to_cpu(al_entry->type) > le32_to_cpu(type)) + goto not_found; + if (type != al_entry->type) + continue; + /* + * If @name is present, compare the two names. If @name is + * missing, assume we want an unnamed attribute. + */ + al_name_len = al_entry->name_length; + al_name = (ntfschar*)((u8*)al_entry + al_entry->name_offset); + if (!name) { + if (al_name_len) + goto not_found; + } else if (!ntfs_are_names_equal(al_name, al_name_len, name, + name_len, ic, vol->upcase, vol->upcase_len)) { + register int rc; + + rc = ntfs_collate_names(name, name_len, al_name, + al_name_len, 1, IGNORE_CASE, + vol->upcase, vol->upcase_len); + /* + * If @name collates before al_name, there is no + * matching attribute. + */ + if (rc == -1) + goto not_found; + /* If the strings are not equal, continue search. */ + if (rc) + continue; + /* + * FIXME: Reverse engineering showed 0, IGNORE_CASE but + * that is inconsistent with ntfs_attr_find(). The + * subsequent rc checks were also different. Perhaps I + * made a mistake in one of the two. Need to recheck + * which is correct or at least see what is going on... + * (AIA) + */ + rc = ntfs_collate_names(name, name_len, al_name, + al_name_len, 1, CASE_SENSITIVE, + vol->upcase, vol->upcase_len); + if (rc == -1) + goto not_found; + if (rc) + continue; + } + /* + * The names match or @name not present and attribute is + * unnamed. Now check @lowest_vcn. Continue search if the + * next attribute list entry still fits @lowest_vcn. Otherwise + * we have reached the right one or the search has failed. + */ + if (lowest_vcn && (u8*)next_al_entry >= al_start && + (u8*)next_al_entry + 6 < al_end && + (u8*)next_al_entry + le16_to_cpu( + next_al_entry->length) <= al_end && + sle64_to_cpu(next_al_entry->lowest_vcn) <= + lowest_vcn && + next_al_entry->type == al_entry->type && + next_al_entry->name_length == al_name_len && + ntfs_are_names_equal((ntfschar*)((u8*) + next_al_entry + + next_al_entry->name_offset), + next_al_entry->name_length, + al_name, al_name_len, CASE_SENSITIVE, + vol->upcase, vol->upcase_len)) + continue; + if (MREF_LE(al_entry->mft_reference) == ni->mft_no) { + if (MSEQNO_LE(al_entry->mft_reference) != ni->seq_no) { + ntfs_error(vol->sb, "Found stale mft " + "reference in attribute list " + "of base inode 0x%lx.%s", + base_ni->mft_no, es); + err = -EIO; + break; + } + } else { /* Mft references do not match. */ + /* If there is a mapped record unmap it first. */ + if (ni != base_ni) + unmap_extent_mft_record(ni); + /* Do we want the base record back? */ + if (MREF_LE(al_entry->mft_reference) == + base_ni->mft_no) { + ni = ctx->ntfs_ino = base_ni; + ctx->mrec = ctx->base_mrec; + } else { + /* We want an extent record. */ + ctx->mrec = map_extent_mft_record(base_ni, + le64_to_cpu( + al_entry->mft_reference), &ni); + if (IS_ERR(ctx->mrec)) { + ntfs_error(vol->sb, "Failed to map " + "extent mft record " + "0x%lx of base inode " + "0x%lx.%s", + MREF_LE(al_entry-> + mft_reference), + base_ni->mft_no, es); + err = PTR_ERR(ctx->mrec); + if (err == -ENOENT) + err = -EIO; + /* Cause @ctx to be sanitized below. */ + ni = NULL; + break; + } + ctx->ntfs_ino = ni; + } + ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec + + le16_to_cpu(ctx->mrec->attrs_offset)); + } + /* + * ctx->vfs_ino, ctx->mrec, and ctx->attr now point to the + * mft record containing the attribute represented by the + * current al_entry. + */ + /* + * We could call into ntfs_attr_find() to find the right + * attribute in this mft record but this would be less + * efficient and not quite accurate as ntfs_attr_find() ignores + * the attribute instance numbers for example which become + * important when one plays with attribute lists. Also, + * because a proper match has been found in the attribute list + * entry above, the comparison can now be optimized. So it is + * worth re-implementing a simplified ntfs_attr_find() here. + */ + a = ctx->attr; + /* + * Use a manual loop so we can still use break and continue + * with the same meanings as above. + */ +do_next_attr_loop: + if ((u8*)a < (u8*)ctx->mrec || (u8*)a > (u8*)ctx->mrec + + le32_to_cpu(ctx->mrec->bytes_allocated)) + break; + if (a->type == AT_END) + break; + if (!a->length) + break; + if (al_entry->instance != a->instance) + goto do_next_attr; + /* + * If the type and/or the name are mismatched between the + * attribute list entry and the attribute record, there is + * corruption so we break and return error EIO. + */ + if (al_entry->type != a->type) + break; + if (!ntfs_are_names_equal((ntfschar*)((u8*)a + + le16_to_cpu(a->name_offset)), a->name_length, + al_name, al_name_len, CASE_SENSITIVE, + vol->upcase, vol->upcase_len)) + break; + ctx->attr = a; + /* + * If no @val specified or @val specified and it matches, we + * have found it! + */ + if (!val || (!a->non_resident && le32_to_cpu( + a->data.resident.value_length) == val_len && + !memcmp((u8*)a + + le16_to_cpu(a->data.resident.value_offset), + val, val_len))) { + ntfs_debug("Done, found."); + return 0; + } +do_next_attr: + /* Proceed to the next attribute in the current mft record. */ + a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length)); + goto do_next_attr_loop; + } + if (!err) { + ntfs_error(vol->sb, "Base inode 0x%lx contains corrupt " + "attribute list attribute.%s", base_ni->mft_no, + es); + err = -EIO; + } + if (ni != base_ni) { + if (ni) + unmap_extent_mft_record(ni); + ctx->ntfs_ino = base_ni; + ctx->mrec = ctx->base_mrec; + ctx->attr = ctx->base_attr; + } + if (err != -ENOMEM) + NVolSetErrors(vol); + return err; +not_found: + /* + * If we were looking for AT_END, we reset the search context @ctx and + * use ntfs_attr_find() to seek to the end of the base mft record. + */ + if (type == AT_END) { + ntfs_attr_reinit_search_ctx(ctx); + return ntfs_attr_find(AT_END, name, name_len, ic, val, val_len, + ctx); + } + /* + * The attribute was not found. Before we return, we want to ensure + * @ctx->mrec and @ctx->attr indicate the position at which the + * attribute should be inserted in the base mft record. Since we also + * want to preserve @ctx->al_entry we cannot reinitialize the search + * context using ntfs_attr_reinit_search_ctx() as this would set + * @ctx->al_entry to NULL. Thus we do the necessary bits manually (see + * ntfs_attr_init_search_ctx() below). Note, we _only_ preserve + * @ctx->al_entry as the remaining fields (base_*) are identical to + * their non base_ counterparts and we cannot set @ctx->base_attr + * correctly yet as we do not know what @ctx->attr will be set to by + * the call to ntfs_attr_find() below. + */ + if (ni != base_ni) + unmap_extent_mft_record(ni); + ctx->mrec = ctx->base_mrec; + ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec + + le16_to_cpu(ctx->mrec->attrs_offset)); + ctx->is_first = true; + ctx->ntfs_ino = base_ni; + ctx->base_ntfs_ino = NULL; + ctx->base_mrec = NULL; + ctx->base_attr = NULL; + /* + * In case there are multiple matches in the base mft record, need to + * keep enumerating until we get an attribute not found response (or + * another error), otherwise we would keep returning the same attribute + * over and over again and all programs using us for enumeration would + * lock up in a tight loop. + */ + do { + err = ntfs_attr_find(type, name, name_len, ic, val, val_len, + ctx); + } while (!err); + ntfs_debug("Done, not found."); + return err; +} + +/** + * ntfs_attr_lookup - find an attribute in an ntfs inode + * @type: attribute type to find + * @name: attribute name to find (optional, i.e. NULL means don't care) + * @name_len: attribute name length (only needed if @name present) + * @ic: IGNORE_CASE or CASE_SENSITIVE (ignored if @name not present) + * @lowest_vcn: lowest vcn to find (optional, non-resident attributes only) + * @val: attribute value to find (optional, resident attributes only) + * @val_len: attribute value length + * @ctx: search context with mft record and attribute to search from + * + * Find an attribute in an ntfs inode. On first search @ctx->ntfs_ino must + * be the base mft record and @ctx must have been obtained from a call to + * ntfs_attr_get_search_ctx(). + * + * This function transparently handles attribute lists and @ctx is used to + * continue searches where they were left off at. + * + * After finishing with the attribute/mft record you need to call + * ntfs_attr_put_search_ctx() to cleanup the search context (unmapping any + * mapped inodes, etc). + * + * Return 0 if the search was successful and -errno if not. + * + * When 0, @ctx->attr is the found attribute and it is in mft record + * @ctx->mrec. If an attribute list attribute is present, @ctx->al_entry is + * the attribute list entry of the found attribute. + * + * When -ENOENT, @ctx->attr is the attribute which collates just after the + * attribute being searched for, i.e. if one wants to add the attribute to the + * mft record this is the correct place to insert it into. If an attribute + * list attribute is present, @ctx->al_entry is the attribute list entry which + * collates just after the attribute list entry of the attribute being searched + * for, i.e. if one wants to add the attribute to the mft record this is the + * correct place to insert its attribute list entry into. + * + * When -errno != -ENOENT, an error occurred during the lookup. @ctx->attr is + * then undefined and in particular you should not rely on it not changing. + */ +int ntfs_attr_lookup(const ATTR_TYPE type, const ntfschar *name, + const u32 name_len, const IGNORE_CASE_BOOL ic, + const VCN lowest_vcn, const u8 *val, const u32 val_len, + ntfs_attr_search_ctx *ctx) +{ + ntfs_inode *base_ni; + + ntfs_debug("Entering."); + BUG_ON(IS_ERR(ctx->mrec)); + if (ctx->base_ntfs_ino) + base_ni = ctx->base_ntfs_ino; + else + base_ni = ctx->ntfs_ino; + /* Sanity check, just for debugging really. */ + BUG_ON(!base_ni); + if (!NInoAttrList(base_ni) || type == AT_ATTRIBUTE_LIST) + return ntfs_attr_find(type, name, name_len, ic, val, val_len, + ctx); + return ntfs_external_attr_find(type, name, name_len, ic, lowest_vcn, + val, val_len, ctx); +} + +/** + * ntfs_attr_init_search_ctx - initialize an attribute search context + * @ctx: attribute search context to initialize + * @ni: ntfs inode with which to initialize the search context + * @mrec: mft record with which to initialize the search context + * + * Initialize the attribute search context @ctx with @ni and @mrec. + */ +static inline void ntfs_attr_init_search_ctx(ntfs_attr_search_ctx *ctx, + ntfs_inode *ni, MFT_RECORD *mrec) +{ + *ctx = (ntfs_attr_search_ctx) { + .mrec = mrec, + /* Sanity checks are performed elsewhere. */ + .attr = (ATTR_RECORD*)((u8*)mrec + + le16_to_cpu(mrec->attrs_offset)), + .is_first = true, + .ntfs_ino = ni, + }; +} + +/** + * ntfs_attr_reinit_search_ctx - reinitialize an attribute search context + * @ctx: attribute search context to reinitialize + * + * Reinitialize the attribute search context @ctx, unmapping an associated + * extent mft record if present, and initialize the search context again. + * + * This is used when a search for a new attribute is being started to reset + * the search context to the beginning. + */ +void ntfs_attr_reinit_search_ctx(ntfs_attr_search_ctx *ctx) +{ + if (likely(!ctx->base_ntfs_ino)) { + /* No attribute list. */ + ctx->is_first = true; + /* Sanity checks are performed elsewhere. */ + ctx->attr = (ATTR_RECORD*)((u8*)ctx->mrec + + le16_to_cpu(ctx->mrec->attrs_offset)); + /* + * This needs resetting due to ntfs_external_attr_find() which + * can leave it set despite having zeroed ctx->base_ntfs_ino. + */ + ctx->al_entry = NULL; + return; + } /* Attribute list. */ + if (ctx->ntfs_ino != ctx->base_ntfs_ino) + unmap_extent_mft_record(ctx->ntfs_ino); + ntfs_attr_init_search_ctx(ctx, ctx->base_ntfs_ino, ctx->base_mrec); + return; +} + +/** + * ntfs_attr_get_search_ctx - allocate/initialize a new attribute search context + * @ni: ntfs inode with which to initialize the search context + * @mrec: mft record with which to initialize the search context + * + * Allocate a new attribute search context, initialize it with @ni and @mrec, + * and return it. Return NULL if allocation failed. + */ +ntfs_attr_search_ctx *ntfs_attr_get_search_ctx(ntfs_inode *ni, MFT_RECORD *mrec) +{ + ntfs_attr_search_ctx *ctx; + + ctx = kmem_cache_alloc(ntfs_attr_ctx_cache, GFP_NOFS); + if (ctx) + ntfs_attr_init_search_ctx(ctx, ni, mrec); + return ctx; +} + +/** + * ntfs_attr_put_search_ctx - release an attribute search context + * @ctx: attribute search context to free + * + * Release the attribute search context @ctx, unmapping an associated extent + * mft record if present. + */ +void ntfs_attr_put_search_ctx(ntfs_attr_search_ctx *ctx) +{ + if (ctx->base_ntfs_ino && ctx->ntfs_ino != ctx->base_ntfs_ino) + unmap_extent_mft_record(ctx->ntfs_ino); + kmem_cache_free(ntfs_attr_ctx_cache, ctx); + return; +} + +#ifdef NTFS_RW + +/** + * ntfs_attr_find_in_attrdef - find an attribute in the $AttrDef system file + * @vol: ntfs volume to which the attribute belongs + * @type: attribute type which to find + * + * Search for the attribute definition record corresponding to the attribute + * @type in the $AttrDef system file. + * + * Return the attribute type definition record if found and NULL if not found. + */ +static ATTR_DEF *ntfs_attr_find_in_attrdef(const ntfs_volume *vol, + const ATTR_TYPE type) +{ + ATTR_DEF *ad; + + BUG_ON(!vol->attrdef); + BUG_ON(!type); + for (ad = vol->attrdef; (u8*)ad - (u8*)vol->attrdef < + vol->attrdef_size && ad->type; ++ad) { + /* We have not found it yet, carry on searching. */ + if (likely(le32_to_cpu(ad->type) < le32_to_cpu(type))) + continue; + /* We found the attribute; return it. */ + if (likely(ad->type == type)) + return ad; + /* We have gone too far already. No point in continuing. */ + break; + } + /* Attribute not found. */ + ntfs_debug("Attribute type 0x%x not found in $AttrDef.", + le32_to_cpu(type)); + return NULL; +} + +/** + * ntfs_attr_size_bounds_check - check a size of an attribute type for validity + * @vol: ntfs volume to which the attribute belongs + * @type: attribute type which to check + * @size: size which to check + * + * Check whether the @size in bytes is valid for an attribute of @type on the + * ntfs volume @vol. This information is obtained from $AttrDef system file. + * + * Return 0 if valid, -ERANGE if not valid, or -ENOENT if the attribute is not + * listed in $AttrDef. + */ +int ntfs_attr_size_bounds_check(const ntfs_volume *vol, const ATTR_TYPE type, + const s64 size) +{ + ATTR_DEF *ad; + + BUG_ON(size < 0); + /* + * $ATTRIBUTE_LIST has a maximum size of 256kiB, but this is not + * listed in $AttrDef. + */ + if (unlikely(type == AT_ATTRIBUTE_LIST && size > 256 * 1024)) + return -ERANGE; + /* Get the $AttrDef entry for the attribute @type. */ + ad = ntfs_attr_find_in_attrdef(vol, type); + if (unlikely(!ad)) + return -ENOENT; + /* Do the bounds check. */ + if (((sle64_to_cpu(ad->min_size) > 0) && + size < sle64_to_cpu(ad->min_size)) || + ((sle64_to_cpu(ad->max_size) > 0) && size > + sle64_to_cpu(ad->max_size))) + return -ERANGE; + return 0; +} + +/** + * ntfs_attr_can_be_non_resident - check if an attribute can be non-resident + * @vol: ntfs volume to which the attribute belongs + * @type: attribute type which to check + * + * Check whether the attribute of @type on the ntfs volume @vol is allowed to + * be non-resident. This information is obtained from $AttrDef system file. + * + * Return 0 if the attribute is allowed to be non-resident, -EPERM if not, and + * -ENOENT if the attribute is not listed in $AttrDef. + */ +int ntfs_attr_can_be_non_resident(const ntfs_volume *vol, const ATTR_TYPE type) +{ + ATTR_DEF *ad; + + /* Find the attribute definition record in $AttrDef. */ + ad = ntfs_attr_find_in_attrdef(vol, type); + if (unlikely(!ad)) + return -ENOENT; + /* Check the flags and return the result. */ + if (ad->flags & ATTR_DEF_RESIDENT) + return -EPERM; + return 0; +} + +/** + * ntfs_attr_can_be_resident - check if an attribute can be resident + * @vol: ntfs volume to which the attribute belongs + * @type: attribute type which to check + * + * Check whether the attribute of @type on the ntfs volume @vol is allowed to + * be resident. This information is derived from our ntfs knowledge and may + * not be completely accurate, especially when user defined attributes are + * present. Basically we allow everything to be resident except for index + * allocation and $EA attributes. + * + * Return 0 if the attribute is allowed to be non-resident and -EPERM if not. + * + * Warning: In the system file $MFT the attribute $Bitmap must be non-resident + * otherwise windows will not boot (blue screen of death)! We cannot + * check for this here as we do not know which inode's $Bitmap is + * being asked about so the caller needs to special case this. + */ +int ntfs_attr_can_be_resident(const ntfs_volume *vol, const ATTR_TYPE type) +{ + if (type == AT_INDEX_ALLOCATION) + return -EPERM; + return 0; +} + +/** + * ntfs_attr_record_resize - resize an attribute record + * @m: mft record containing attribute record + * @a: attribute record to resize + * @new_size: new size in bytes to which to resize the attribute record @a + * + * Resize the attribute record @a, i.e. the resident part of the attribute, in + * the mft record @m to @new_size bytes. + * + * Return 0 on success and -errno on error. The following error codes are + * defined: + * -ENOSPC - Not enough space in the mft record @m to perform the resize. + * + * Note: On error, no modifications have been performed whatsoever. + * + * Warning: If you make a record smaller without having copied all the data you + * are interested in the data may be overwritten. + */ +int ntfs_attr_record_resize(MFT_RECORD *m, ATTR_RECORD *a, u32 new_size) +{ + ntfs_debug("Entering for new_size %u.", new_size); + /* Align to 8 bytes if it is not already done. */ + if (new_size & 7) + new_size = (new_size + 7) & ~7; + /* If the actual attribute length has changed, move things around. */ + if (new_size != le32_to_cpu(a->length)) { + u32 new_muse = le32_to_cpu(m->bytes_in_use) - + le32_to_cpu(a->length) + new_size; + /* Not enough space in this mft record. */ + if (new_muse > le32_to_cpu(m->bytes_allocated)) + return -ENOSPC; + /* Move attributes following @a to their new location. */ + memmove((u8*)a + new_size, (u8*)a + le32_to_cpu(a->length), + le32_to_cpu(m->bytes_in_use) - ((u8*)a - + (u8*)m) - le32_to_cpu(a->length)); + /* Adjust @m to reflect the change in used space. */ + m->bytes_in_use = cpu_to_le32(new_muse); + /* Adjust @a to reflect the new size. */ + if (new_size >= offsetof(ATTR_REC, length) + sizeof(a->length)) + a->length = cpu_to_le32(new_size); + } + return 0; +} + +/** + * ntfs_resident_attr_value_resize - resize the value of a resident attribute + * @m: mft record containing attribute record + * @a: attribute record whose value to resize + * @new_size: new size in bytes to which to resize the attribute value of @a + * + * Resize the value of the attribute @a in the mft record @m to @new_size bytes. + * If the value is made bigger, the newly allocated space is cleared. + * + * Return 0 on success and -errno on error. The following error codes are + * defined: + * -ENOSPC - Not enough space in the mft record @m to perform the resize. + * + * Note: On error, no modifications have been performed whatsoever. + * + * Warning: If you make a record smaller without having copied all the data you + * are interested in the data may be overwritten. + */ +int ntfs_resident_attr_value_resize(MFT_RECORD *m, ATTR_RECORD *a, + const u32 new_size) +{ + u32 old_size; + + /* Resize the resident part of the attribute record. */ + if (ntfs_attr_record_resize(m, a, + le16_to_cpu(a->data.resident.value_offset) + new_size)) + return -ENOSPC; + /* + * The resize succeeded! If we made the attribute value bigger, clear + * the area between the old size and @new_size. + */ + old_size = le32_to_cpu(a->data.resident.value_length); + if (new_size > old_size) + memset((u8*)a + le16_to_cpu(a->data.resident.value_offset) + + old_size, 0, new_size - old_size); + /* Finally update the length of the attribute value. */ + a->data.resident.value_length = cpu_to_le32(new_size); + return 0; +} + +/** + * ntfs_attr_make_non_resident - convert a resident to a non-resident attribute + * @ni: ntfs inode describing the attribute to convert + * @data_size: size of the resident data to copy to the non-resident attribute + * + * Convert the resident ntfs attribute described by the ntfs inode @ni to a + * non-resident one. + * + * @data_size must be equal to the attribute value size. This is needed since + * we need to know the size before we can map the mft record and our callers + * always know it. The reason we cannot simply read the size from the vfs + * inode i_size is that this is not necessarily uptodate. This happens when + * ntfs_attr_make_non_resident() is called in the ->truncate call path(s). + * + * Return 0 on success and -errno on error. The following error return codes + * are defined: + * -EPERM - The attribute is not allowed to be non-resident. + * -ENOMEM - Not enough memory. + * -ENOSPC - Not enough disk space. + * -EINVAL - Attribute not defined on the volume. + * -EIO - I/o error or other error. + * Note that -ENOSPC is also returned in the case that there is not enough + * space in the mft record to do the conversion. This can happen when the mft + * record is already very full. The caller is responsible for trying to make + * space in the mft record and trying again. FIXME: Do we need a separate + * error return code for this kind of -ENOSPC or is it always worth trying + * again in case the attribute may then fit in a resident state so no need to + * make it non-resident at all? Ho-hum... (AIA) + * + * NOTE to self: No changes in the attribute list are required to move from + * a resident to a non-resident attribute. + * + * Locking: - The caller must hold i_mutex on the inode. + */ +int ntfs_attr_make_non_resident(ntfs_inode *ni, const u32 data_size) +{ + s64 new_size; + struct inode *vi = VFS_I(ni); + ntfs_volume *vol = ni->vol; + ntfs_inode *base_ni; + MFT_RECORD *m; + ATTR_RECORD *a; + ntfs_attr_search_ctx *ctx; + struct page *page; + runlist_element *rl; + u8 *kaddr; + unsigned long flags; + int mp_size, mp_ofs, name_ofs, arec_size, err, err2; + u32 attr_size; + u8 old_res_attr_flags; + + /* Check that the attribute is allowed to be non-resident. */ + err = ntfs_attr_can_be_non_resident(vol, ni->type); + if (unlikely(err)) { + if (err == -EPERM) + ntfs_debug("Attribute is not allowed to be " + "non-resident."); + else + ntfs_debug("Attribute not defined on the NTFS " + "volume!"); + return err; + } + /* + * FIXME: Compressed and encrypted attributes are not supported when + * writing and we should never have gotten here for them. + */ + BUG_ON(NInoCompressed(ni)); + BUG_ON(NInoEncrypted(ni)); + /* + * The size needs to be aligned to a cluster boundary for allocation + * purposes. + */ + new_size = (data_size + vol->cluster_size - 1) & + ~(vol->cluster_size - 1); + if (new_size > 0) { + /* + * Will need the page later and since the page lock nests + * outside all ntfs locks, we need to get the page now. + */ + page = find_or_create_page(vi->i_mapping, 0, + mapping_gfp_mask(vi->i_mapping)); + if (unlikely(!page)) + return -ENOMEM; + /* Start by allocating clusters to hold the attribute value. */ + rl = ntfs_cluster_alloc(vol, 0, new_size >> + vol->cluster_size_bits, -1, DATA_ZONE, true); + if (IS_ERR(rl)) { + err = PTR_ERR(rl); + ntfs_debug("Failed to allocate cluster%s, error code " + "%i.", (new_size >> + vol->cluster_size_bits) > 1 ? "s" : "", + err); + goto page_err_out; + } + } else { + rl = NULL; + page = NULL; + } + /* Determine the size of the mapping pairs array. */ + mp_size = ntfs_get_size_for_mapping_pairs(vol, rl, 0, -1); + if (unlikely(mp_size < 0)) { + err = mp_size; + ntfs_debug("Failed to get size for mapping pairs array, error " + "code %i.", err); + goto rl_err_out; + } + down_write(&ni->runlist.lock); + if (!NInoAttr(ni)) + base_ni = ni; + else + base_ni = ni->ext.base_ntfs_ino; + m = map_mft_record(base_ni); + if (IS_ERR(m)) { + err = PTR_ERR(m); + m = NULL; + ctx = NULL; + goto err_out; + } + ctx = ntfs_attr_get_search_ctx(base_ni, m); + if (unlikely(!ctx)) { + err = -ENOMEM; + goto err_out; + } + err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len, + CASE_SENSITIVE, 0, NULL, 0, ctx); + if (unlikely(err)) { + if (err == -ENOENT) + err = -EIO; + goto err_out; + } + m = ctx->mrec; + a = ctx->attr; + BUG_ON(NInoNonResident(ni)); + BUG_ON(a->non_resident); + /* + * Calculate new offsets for the name and the mapping pairs array. + */ + if (NInoSparse(ni) || NInoCompressed(ni)) + name_ofs = (offsetof(ATTR_REC, + data.non_resident.compressed_size) + + sizeof(a->data.non_resident.compressed_size) + + 7) & ~7; + else + name_ofs = (offsetof(ATTR_REC, + data.non_resident.compressed_size) + 7) & ~7; + mp_ofs = (name_ofs + a->name_length * sizeof(ntfschar) + 7) & ~7; + /* + * Determine the size of the resident part of the now non-resident + * attribute record. + */ + arec_size = (mp_ofs + mp_size + 7) & ~7; + /* + * If the page is not uptodate bring it uptodate by copying from the + * attribute value. + */ + attr_size = le32_to_cpu(a->data.resident.value_length); + BUG_ON(attr_size != data_size); + if (page && !PageUptodate(page)) { + kaddr = kmap_atomic(page); + memcpy(kaddr, (u8*)a + + le16_to_cpu(a->data.resident.value_offset), + attr_size); + memset(kaddr + attr_size, 0, PAGE_CACHE_SIZE - attr_size); + kunmap_atomic(kaddr); + flush_dcache_page(page); + SetPageUptodate(page); + } + /* Backup the attribute flag. */ + old_res_attr_flags = a->data.resident.flags; + /* Resize the resident part of the attribute record. */ + err = ntfs_attr_record_resize(m, a, arec_size); + if (unlikely(err)) + goto err_out; + /* + * Convert the resident part of the attribute record to describe a + * non-resident attribute. + */ + a->non_resident = 1; + /* Move the attribute name if it exists and update the offset. */ + if (a->name_length) + memmove((u8*)a + name_ofs, (u8*)a + le16_to_cpu(a->name_offset), + a->name_length * sizeof(ntfschar)); + a->name_offset = cpu_to_le16(name_ofs); + /* Setup the fields specific to non-resident attributes. */ + a->data.non_resident.lowest_vcn = 0; + a->data.non_resident.highest_vcn = cpu_to_sle64((new_size - 1) >> + vol->cluster_size_bits); + a->data.non_resident.mapping_pairs_offset = cpu_to_le16(mp_ofs); + memset(&a->data.non_resident.reserved, 0, + sizeof(a->data.non_resident.reserved)); + a->data.non_resident.allocated_size = cpu_to_sle64(new_size); + a->data.non_resident.data_size = + a->data.non_resident.initialized_size = + cpu_to_sle64(attr_size); + if (NInoSparse(ni) || NInoCompressed(ni)) { + a->data.non_resident.compression_unit = 0; + if (NInoCompressed(ni) || vol->major_ver < 3) + a->data.non_resident.compression_unit = 4; + a->data.non_resident.compressed_size = + a->data.non_resident.allocated_size; + } else + a->data.non_resident.compression_unit = 0; + /* Generate the mapping pairs array into the attribute record. */ + err = ntfs_mapping_pairs_build(vol, (u8*)a + mp_ofs, + arec_size - mp_ofs, rl, 0, -1, NULL); + if (unlikely(err)) { + ntfs_debug("Failed to build mapping pairs, error code %i.", + err); + goto undo_err_out; + } + /* Setup the in-memory attribute structure to be non-resident. */ + ni->runlist.rl = rl; + write_lock_irqsave(&ni->size_lock, flags); + ni->allocated_size = new_size; + if (NInoSparse(ni) || NInoCompressed(ni)) { + ni->itype.compressed.size = ni->allocated_size; + if (a->data.non_resident.compression_unit) { + ni->itype.compressed.block_size = 1U << (a->data. + non_resident.compression_unit + + vol->cluster_size_bits); + ni->itype.compressed.block_size_bits = + ffs(ni->itype.compressed.block_size) - + 1; + ni->itype.compressed.block_clusters = 1U << + a->data.non_resident.compression_unit; + } else { + ni->itype.compressed.block_size = 0; + ni->itype.compressed.block_size_bits = 0; + ni->itype.compressed.block_clusters = 0; + } + vi->i_blocks = ni->itype.compressed.size >> 9; + } else + vi->i_blocks = ni->allocated_size >> 9; + write_unlock_irqrestore(&ni->size_lock, flags); + /* + * This needs to be last since the address space operations ->readpage + * and ->writepage can run concurrently with us as they are not + * serialized on i_mutex. Note, we are not allowed to fail once we flip + * this switch, which is another reason to do this last. + */ + NInoSetNonResident(ni); + /* Mark the mft record dirty, so it gets written back. */ + flush_dcache_mft_record_page(ctx->ntfs_ino); + mark_mft_record_dirty(ctx->ntfs_ino); + ntfs_attr_put_search_ctx(ctx); + unmap_mft_record(base_ni); + up_write(&ni->runlist.lock); + if (page) { + set_page_dirty(page); + unlock_page(page); + page_cache_release(page); + } + ntfs_debug("Done."); + return 0; +undo_err_out: + /* Convert the attribute back into a resident attribute. */ + a->non_resident = 0; + /* Move the attribute name if it exists and update the offset. */ + name_ofs = (offsetof(ATTR_RECORD, data.resident.reserved) + + sizeof(a->data.resident.reserved) + 7) & ~7; + if (a->name_length) + memmove((u8*)a + name_ofs, (u8*)a + le16_to_cpu(a->name_offset), + a->name_length * sizeof(ntfschar)); + mp_ofs = (name_ofs + a->name_length * sizeof(ntfschar) + 7) & ~7; + a->name_offset = cpu_to_le16(name_ofs); + arec_size = (mp_ofs + attr_size + 7) & ~7; + /* Resize the resident part of the attribute record. */ + err2 = ntfs_attr_record_resize(m, a, arec_size); + if (unlikely(err2)) { + /* + * This cannot happen (well if memory corruption is at work it + * could happen in theory), but deal with it as well as we can. + * If the old size is too small, truncate the attribute, + * otherwise simply give it a larger allocated size. + * FIXME: Should check whether chkdsk complains when the + * allocated size is much bigger than the resident value size. + */ + arec_size = le32_to_cpu(a->length); + if ((mp_ofs + attr_size) > arec_size) { + err2 = attr_size; + attr_size = arec_size - mp_ofs; + ntfs_error(vol->sb, "Failed to undo partial resident " + "to non-resident attribute " + "conversion. Truncating inode 0x%lx, " + "attribute type 0x%x from %i bytes to " + "%i bytes to maintain metadata " + "consistency. THIS MEANS YOU ARE " + "LOSING %i BYTES DATA FROM THIS %s.", + vi->i_ino, + (unsigned)le32_to_cpu(ni->type), + err2, attr_size, err2 - attr_size, + ((ni->type == AT_DATA) && + !ni->name_len) ? "FILE": "ATTRIBUTE"); + write_lock_irqsave(&ni->size_lock, flags); + ni->initialized_size = attr_size; + i_size_write(vi, attr_size); + write_unlock_irqrestore(&ni->size_lock, flags); + } + } + /* Setup the fields specific to resident attributes. */ + a->data.resident.value_length = cpu_to_le32(attr_size); + a->data.resident.value_offset = cpu_to_le16(mp_ofs); + a->data.resident.flags = old_res_attr_flags; + memset(&a->data.resident.reserved, 0, + sizeof(a->data.resident.reserved)); + /* Copy the data from the page back to the attribute value. */ + if (page) { + kaddr = kmap_atomic(page); + memcpy((u8*)a + mp_ofs, kaddr, attr_size); + kunmap_atomic(kaddr); + } + /* Setup the allocated size in the ntfs inode in case it changed. */ + write_lock_irqsave(&ni->size_lock, flags); + ni->allocated_size = arec_size - mp_ofs; + write_unlock_irqrestore(&ni->size_lock, flags); + /* Mark the mft record dirty, so it gets written back. */ + flush_dcache_mft_record_page(ctx->ntfs_ino); + mark_mft_record_dirty(ctx->ntfs_ino); +err_out: + if (ctx) + ntfs_attr_put_search_ctx(ctx); + if (m) + unmap_mft_record(base_ni); + ni->runlist.rl = NULL; + up_write(&ni->runlist.lock); +rl_err_out: + if (rl) { + if (ntfs_cluster_free_from_rl(vol, rl) < 0) { + ntfs_error(vol->sb, "Failed to release allocated " + "cluster(s) in error code path. Run " + "chkdsk to recover the lost " + "cluster(s)."); + NVolSetErrors(vol); + } + ntfs_free(rl); +page_err_out: + unlock_page(page); + page_cache_release(page); + } + if (err == -EINVAL) + err = -EIO; + return err; +} + +/** + * ntfs_attr_extend_allocation - extend the allocated space of an attribute + * @ni: ntfs inode of the attribute whose allocation to extend + * @new_alloc_size: new size in bytes to which to extend the allocation to + * @new_data_size: new size in bytes to which to extend the data to + * @data_start: beginning of region which is required to be non-sparse + * + * Extend the allocated space of an attribute described by the ntfs inode @ni + * to @new_alloc_size bytes. If @data_start is -1, the whole extension may be + * implemented as a hole in the file (as long as both the volume and the ntfs + * inode @ni have sparse support enabled). If @data_start is >= 0, then the + * region between the old allocated size and @data_start - 1 may be made sparse + * but the regions between @data_start and @new_alloc_size must be backed by + * actual clusters. + * + * If @new_data_size is -1, it is ignored. If it is >= 0, then the data size + * of the attribute is extended to @new_data_size. Note that the i_size of the + * vfs inode is not updated. Only the data size in the base attribute record + * is updated. The caller has to update i_size separately if this is required. + * WARNING: It is a BUG() for @new_data_size to be smaller than the old data + * size as well as for @new_data_size to be greater than @new_alloc_size. + * + * For resident attributes this involves resizing the attribute record and if + * necessary moving it and/or other attributes into extent mft records and/or + * converting the attribute to a non-resident attribute which in turn involves + * extending the allocation of a non-resident attribute as described below. + * + * For non-resident attributes this involves allocating clusters in the data + * zone on the volume (except for regions that are being made sparse) and + * extending the run list to describe the allocated clusters as well as + * updating the mapping pairs array of the attribute. This in turn involves + * resizing the attribute record and if necessary moving it and/or other + * attributes into extent mft records and/or splitting the attribute record + * into multiple extent attribute records. + * + * Also, the attribute list attribute is updated if present and in some of the + * above cases (the ones where extent mft records/attributes come into play), + * an attribute list attribute is created if not already present. + * + * Return the new allocated size on success and -errno on error. In the case + * that an error is encountered but a partial extension at least up to + * @data_start (if present) is possible, the allocation is partially extended + * and this is returned. This means the caller must check the returned size to + * determine if the extension was partial. If @data_start is -1 then partial + * allocations are not performed. + * + * WARNING: Do not call ntfs_attr_extend_allocation() for $MFT/$DATA. + * + * Locking: This function takes the runlist lock of @ni for writing as well as + * locking the mft record of the base ntfs inode. These locks are maintained + * throughout execution of the function. These locks are required so that the + * attribute can be resized safely and so that it can for example be converted + * from resident to non-resident safely. + * + * TODO: At present attribute list attribute handling is not implemented. + * + * TODO: At present it is not safe to call this function for anything other + * than the $DATA attribute(s) of an uncompressed and unencrypted file. + */ +s64 ntfs_attr_extend_allocation(ntfs_inode *ni, s64 new_alloc_size, + const s64 new_data_size, const s64 data_start) +{ + VCN vcn; + s64 ll, allocated_size, start = data_start; + struct inode *vi = VFS_I(ni); + ntfs_volume *vol = ni->vol; + ntfs_inode *base_ni; + MFT_RECORD *m; + ATTR_RECORD *a; + ntfs_attr_search_ctx *ctx; + runlist_element *rl, *rl2; + unsigned long flags; + int err, mp_size; + u32 attr_len = 0; /* Silence stupid gcc warning. */ + bool mp_rebuilt; + +#ifdef DEBUG + read_lock_irqsave(&ni->size_lock, flags); + allocated_size = ni->allocated_size; + read_unlock_irqrestore(&ni->size_lock, flags); + ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, " + "old_allocated_size 0x%llx, " + "new_allocated_size 0x%llx, new_data_size 0x%llx, " + "data_start 0x%llx.", vi->i_ino, + (unsigned)le32_to_cpu(ni->type), + (unsigned long long)allocated_size, + (unsigned long long)new_alloc_size, + (unsigned long long)new_data_size, + (unsigned long long)start); +#endif +retry_extend: + /* + * For non-resident attributes, @start and @new_size need to be aligned + * to cluster boundaries for allocation purposes. + */ + if (NInoNonResident(ni)) { + if (start > 0) + start &= ~(s64)vol->cluster_size_mask; + new_alloc_size = (new_alloc_size + vol->cluster_size - 1) & + ~(s64)vol->cluster_size_mask; + } + BUG_ON(new_data_size >= 0 && new_data_size > new_alloc_size); + /* Check if new size is allowed in $AttrDef. */ + err = ntfs_attr_size_bounds_check(vol, ni->type, new_alloc_size); + if (unlikely(err)) { + /* Only emit errors when the write will fail completely. */ + read_lock_irqsave(&ni->size_lock, flags); + allocated_size = ni->allocated_size; + read_unlock_irqrestore(&ni->size_lock, flags); + if (start < 0 || start >= allocated_size) { + if (err == -ERANGE) { + ntfs_error(vol->sb, "Cannot extend allocation " + "of inode 0x%lx, attribute " + "type 0x%x, because the new " + "allocation would exceed the " + "maximum allowed size for " + "this attribute type.", + vi->i_ino, (unsigned) + le32_to_cpu(ni->type)); + } else { + ntfs_error(vol->sb, "Cannot extend allocation " + "of inode 0x%lx, attribute " + "type 0x%x, because this " + "attribute type is not " + "defined on the NTFS volume. " + "Possible corruption! You " + "should run chkdsk!", + vi->i_ino, (unsigned) + le32_to_cpu(ni->type)); + } + } + /* Translate error code to be POSIX conformant for write(2). */ + if (err == -ERANGE) + err = -EFBIG; + else + err = -EIO; + return err; + } + if (!NInoAttr(ni)) + base_ni = ni; + else + base_ni = ni->ext.base_ntfs_ino; + /* + * We will be modifying both the runlist (if non-resident) and the mft + * record so lock them both down. + */ + down_write(&ni->runlist.lock); + m = map_mft_record(base_ni); + if (IS_ERR(m)) { + err = PTR_ERR(m); + m = NULL; + ctx = NULL; + goto err_out; + } + ctx = ntfs_attr_get_search_ctx(base_ni, m); + if (unlikely(!ctx)) { + err = -ENOMEM; + goto err_out; + } + read_lock_irqsave(&ni->size_lock, flags); + allocated_size = ni->allocated_size; + read_unlock_irqrestore(&ni->size_lock, flags); + /* + * If non-resident, seek to the last extent. If resident, there is + * only one extent, so seek to that. + */ + vcn = NInoNonResident(ni) ? allocated_size >> vol->cluster_size_bits : + 0; + /* + * Abort if someone did the work whilst we waited for the locks. If we + * just converted the attribute from resident to non-resident it is + * likely that exactly this has happened already. We cannot quite + * abort if we need to update the data size. + */ + if (unlikely(new_alloc_size <= allocated_size)) { + ntfs_debug("Allocated size already exceeds requested size."); + new_alloc_size = allocated_size; + if (new_data_size < 0) + goto done; + /* + * We want the first attribute extent so that we can update the + * data size. + */ + vcn = 0; + } + err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len, + CASE_SENSITIVE, vcn, NULL, 0, ctx); + if (unlikely(err)) { + if (err == -ENOENT) + err = -EIO; + goto err_out; + } + m = ctx->mrec; + a = ctx->attr; + /* Use goto to reduce indentation. */ + if (a->non_resident) + goto do_non_resident_extend; + BUG_ON(NInoNonResident(ni)); + /* The total length of the attribute value. */ + attr_len = le32_to_cpu(a->data.resident.value_length); + /* + * Extend the attribute record to be able to store the new attribute + * size. ntfs_attr_record_resize() will not do anything if the size is + * not changing. + */ + if (new_alloc_size < vol->mft_record_size && + !ntfs_attr_record_resize(m, a, + le16_to_cpu(a->data.resident.value_offset) + + new_alloc_size)) { + /* The resize succeeded! */ + write_lock_irqsave(&ni->size_lock, flags); + ni->allocated_size = le32_to_cpu(a->length) - + le16_to_cpu(a->data.resident.value_offset); + write_unlock_irqrestore(&ni->size_lock, flags); + if (new_data_size >= 0) { + BUG_ON(new_data_size < attr_len); + a->data.resident.value_length = + cpu_to_le32((u32)new_data_size); + } + goto flush_done; + } + /* + * We have to drop all the locks so we can call + * ntfs_attr_make_non_resident(). This could be optimised by try- + * locking the first page cache page and only if that fails dropping + * the locks, locking the page, and redoing all the locking and + * lookups. While this would be a huge optimisation, it is not worth + * it as this is definitely a slow code path. + */ + ntfs_attr_put_search_ctx(ctx); + unmap_mft_record(base_ni); + up_write(&ni->runlist.lock); + /* + * Not enough space in the mft record, try to make the attribute + * non-resident and if successful restart the extension process. + */ + err = ntfs_attr_make_non_resident(ni, attr_len); + if (likely(!err)) + goto retry_extend; + /* + * Could not make non-resident. If this is due to this not being + * permitted for this attribute type or there not being enough space, + * try to make other attributes non-resident. Otherwise fail. + */ + if (unlikely(err != -EPERM && err != -ENOSPC)) { + /* Only emit errors when the write will fail completely. */ + read_lock_irqsave(&ni->size_lock, flags); + allocated_size = ni->allocated_size; + read_unlock_irqrestore(&ni->size_lock, flags); + if (start < 0 || start >= allocated_size) + ntfs_error(vol->sb, "Cannot extend allocation of " + "inode 0x%lx, attribute type 0x%x, " + "because the conversion from resident " + "to non-resident attribute failed " + "with error code %i.", vi->i_ino, + (unsigned)le32_to_cpu(ni->type), err); + if (err != -ENOMEM) + err = -EIO; + goto conv_err_out; + } + /* TODO: Not implemented from here, abort. */ + read_lock_irqsave(&ni->size_lock, flags); + allocated_size = ni->allocated_size; + read_unlock_irqrestore(&ni->size_lock, flags); + if (start < 0 || start >= allocated_size) { + if (err == -ENOSPC) + ntfs_error(vol->sb, "Not enough space in the mft " + "record/on disk for the non-resident " + "attribute value. This case is not " + "implemented yet."); + else /* if (err == -EPERM) */ + ntfs_error(vol->sb, "This attribute type may not be " + "non-resident. This case is not " + "implemented yet."); + } + err = -EOPNOTSUPP; + goto conv_err_out; +#if 0 + // TODO: Attempt to make other attributes non-resident. + if (!err) + goto do_resident_extend; + /* + * Both the attribute list attribute and the standard information + * attribute must remain in the base inode. Thus, if this is one of + * these attributes, we have to try to move other attributes out into + * extent mft records instead. + */ + if (ni->type == AT_ATTRIBUTE_LIST || + ni->type == AT_STANDARD_INFORMATION) { + // TODO: Attempt to move other attributes into extent mft + // records. + err = -EOPNOTSUPP; + if (!err) + goto do_resident_extend; + goto err_out; + } + // TODO: Attempt to move this attribute to an extent mft record, but + // only if it is not already the only attribute in an mft record in + // which case there would be nothing to gain. + err = -EOPNOTSUPP; + if (!err) + goto do_resident_extend; + /* There is nothing we can do to make enough space. )-: */ + goto err_out; +#endif +do_non_resident_extend: + BUG_ON(!NInoNonResident(ni)); + if (new_alloc_size == allocated_size) { + BUG_ON(vcn); + goto alloc_done; + } + /* + * If the data starts after the end of the old allocation, this is a + * $DATA attribute and sparse attributes are enabled on the volume and + * for this inode, then create a sparse region between the old + * allocated size and the start of the data. Otherwise simply proceed + * with filling the whole space between the old allocated size and the + * new allocated size with clusters. + */ + if ((start >= 0 && start <= allocated_size) || ni->type != AT_DATA || + !NVolSparseEnabled(vol) || NInoSparseDisabled(ni)) + goto skip_sparse; + // TODO: This is not implemented yet. We just fill in with real + // clusters for now... + ntfs_debug("Inserting holes is not-implemented yet. Falling back to " + "allocating real clusters instead."); +skip_sparse: + rl = ni->runlist.rl; + if (likely(rl)) { + /* Seek to the end of the runlist. */ + while (rl->length) + rl++; + } + /* If this attribute extent is not mapped, map it now. */ + if (unlikely(!rl || rl->lcn == LCN_RL_NOT_MAPPED || + (rl->lcn == LCN_ENOENT && rl > ni->runlist.rl && + (rl-1)->lcn == LCN_RL_NOT_MAPPED))) { + if (!rl && !allocated_size) + goto first_alloc; + rl = ntfs_mapping_pairs_decompress(vol, a, ni->runlist.rl); + if (IS_ERR(rl)) { + err = PTR_ERR(rl); + if (start < 0 || start >= allocated_size) + ntfs_error(vol->sb, "Cannot extend allocation " + "of inode 0x%lx, attribute " + "type 0x%x, because the " + "mapping of a runlist " + "fragment failed with error " + "code %i.", vi->i_ino, + (unsigned)le32_to_cpu(ni->type), + err); + if (err != -ENOMEM) + err = -EIO; + goto err_out; + } + ni->runlist.rl = rl; + /* Seek to the end of the runlist. */ + while (rl->length) + rl++; + } + /* + * We now know the runlist of the last extent is mapped and @rl is at + * the end of the runlist. We want to begin allocating clusters + * starting at the last allocated cluster to reduce fragmentation. If + * there are no valid LCNs in the attribute we let the cluster + * allocator choose the starting cluster. + */ + /* If the last LCN is a hole or simillar seek back to last real LCN. */ + while (rl->lcn < 0 && rl > ni->runlist.rl) + rl--; +first_alloc: + // FIXME: Need to implement partial allocations so at least part of the + // write can be performed when start >= 0. (Needed for POSIX write(2) + // conformance.) + rl2 = ntfs_cluster_alloc(vol, allocated_size >> vol->cluster_size_bits, + (new_alloc_size - allocated_size) >> + vol->cluster_size_bits, (rl && (rl->lcn >= 0)) ? + rl->lcn + rl->length : -1, DATA_ZONE, true); + if (IS_ERR(rl2)) { + err = PTR_ERR(rl2); + if (start < 0 || start >= allocated_size) + ntfs_error(vol->sb, "Cannot extend allocation of " + "inode 0x%lx, attribute type 0x%x, " + "because the allocation of clusters " + "failed with error code %i.", vi->i_ino, + (unsigned)le32_to_cpu(ni->type), err); + if (err != -ENOMEM && err != -ENOSPC) + err = -EIO; + goto err_out; + } + rl = ntfs_runlists_merge(ni->runlist.rl, rl2); + if (IS_ERR(rl)) { + err = PTR_ERR(rl); + if (start < 0 || start >= allocated_size) + ntfs_error(vol->sb, "Cannot extend allocation of " + "inode 0x%lx, attribute type 0x%x, " + "because the runlist merge failed " + "with error code %i.", vi->i_ino, + (unsigned)le32_to_cpu(ni->type), err); + if (err != -ENOMEM) + err = -EIO; + if (ntfs_cluster_free_from_rl(vol, rl2)) { + ntfs_error(vol->sb, "Failed to release allocated " + "cluster(s) in error code path. Run " + "chkdsk to recover the lost " + "cluster(s)."); + NVolSetErrors(vol); + } + ntfs_free(rl2); + goto err_out; + } + ni->runlist.rl = rl; + ntfs_debug("Allocated 0x%llx clusters.", (long long)(new_alloc_size - + allocated_size) >> vol->cluster_size_bits); + /* Find the runlist element with which the attribute extent starts. */ + ll = sle64_to_cpu(a->data.non_resident.lowest_vcn); + rl2 = ntfs_rl_find_vcn_nolock(rl, ll); + BUG_ON(!rl2); + BUG_ON(!rl2->length); + BUG_ON(rl2->lcn < LCN_HOLE); + mp_rebuilt = false; + /* Get the size for the new mapping pairs array for this extent. */ + mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1); + if (unlikely(mp_size <= 0)) { + err = mp_size; + if (start < 0 || start >= allocated_size) + ntfs_error(vol->sb, "Cannot extend allocation of " + "inode 0x%lx, attribute type 0x%x, " + "because determining the size for the " + "mapping pairs failed with error code " + "%i.", vi->i_ino, + (unsigned)le32_to_cpu(ni->type), err); + err = -EIO; + goto undo_alloc; + } + /* Extend the attribute record to fit the bigger mapping pairs array. */ + attr_len = le32_to_cpu(a->length); + err = ntfs_attr_record_resize(m, a, mp_size + + le16_to_cpu(a->data.non_resident.mapping_pairs_offset)); + if (unlikely(err)) { + BUG_ON(err != -ENOSPC); + // TODO: Deal with this by moving this extent to a new mft + // record or by starting a new extent in a new mft record, + // possibly by extending this extent partially and filling it + // and creating a new extent for the remainder, or by making + // other attributes non-resident and/or by moving other + // attributes out of this mft record. + if (start < 0 || start >= allocated_size) + ntfs_error(vol->sb, "Not enough space in the mft " + "record for the extended attribute " + "record. This case is not " + "implemented yet."); + err = -EOPNOTSUPP; + goto undo_alloc; + } + mp_rebuilt = true; + /* Generate the mapping pairs array directly into the attr record. */ + err = ntfs_mapping_pairs_build(vol, (u8*)a + + le16_to_cpu(a->data.non_resident.mapping_pairs_offset), + mp_size, rl2, ll, -1, NULL); + if (unlikely(err)) { + if (start < 0 || start >= allocated_size) + ntfs_error(vol->sb, "Cannot extend allocation of " + "inode 0x%lx, attribute type 0x%x, " + "because building the mapping pairs " + "failed with error code %i.", vi->i_ino, + (unsigned)le32_to_cpu(ni->type), err); + err = -EIO; + goto undo_alloc; + } + /* Update the highest_vcn. */ + a->data.non_resident.highest_vcn = cpu_to_sle64((new_alloc_size >> + vol->cluster_size_bits) - 1); + /* + * We now have extended the allocated size of the attribute. Reflect + * this in the ntfs_inode structure and the attribute record. + */ + if (a->data.non_resident.lowest_vcn) { + /* + * We are not in the first attribute extent, switch to it, but + * first ensure the changes will make it to disk later. + */ + flush_dcache_mft_record_page(ctx->ntfs_ino); + mark_mft_record_dirty(ctx->ntfs_ino); + ntfs_attr_reinit_search_ctx(ctx); + err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len, + CASE_SENSITIVE, 0, NULL, 0, ctx); + if (unlikely(err)) + goto restore_undo_alloc; + /* @m is not used any more so no need to set it. */ + a = ctx->attr; + } + write_lock_irqsave(&ni->size_lock, flags); + ni->allocated_size = new_alloc_size; + a->data.non_resident.allocated_size = cpu_to_sle64(new_alloc_size); + /* + * FIXME: This would fail if @ni is a directory, $MFT, or an index, + * since those can have sparse/compressed set. For example can be + * set compressed even though it is not compressed itself and in that + * case the bit means that files are to be created compressed in the + * directory... At present this is ok as this code is only called for + * regular files, and only for their $DATA attribute(s). + * FIXME: The calculation is wrong if we created a hole above. For now + * it does not matter as we never create holes. + */ + if (NInoSparse(ni) || NInoCompressed(ni)) { + ni->itype.compressed.size += new_alloc_size - allocated_size; + a->data.non_resident.compressed_size = + cpu_to_sle64(ni->itype.compressed.size); + vi->i_blocks = ni->itype.compressed.size >> 9; + } else + vi->i_blocks = new_alloc_size >> 9; + write_unlock_irqrestore(&ni->size_lock, flags); +alloc_done: + if (new_data_size >= 0) { + BUG_ON(new_data_size < + sle64_to_cpu(a->data.non_resident.data_size)); + a->data.non_resident.data_size = cpu_to_sle64(new_data_size); + } +flush_done: + /* Ensure the changes make it to disk. */ + flush_dcache_mft_record_page(ctx->ntfs_ino); + mark_mft_record_dirty(ctx->ntfs_ino); +done: + ntfs_attr_put_search_ctx(ctx); + unmap_mft_record(base_ni); + up_write(&ni->runlist.lock); + ntfs_debug("Done, new_allocated_size 0x%llx.", + (unsigned long long)new_alloc_size); + return new_alloc_size; +restore_undo_alloc: + if (start < 0 || start >= allocated_size) + ntfs_error(vol->sb, "Cannot complete extension of allocation " + "of inode 0x%lx, attribute type 0x%x, because " + "lookup of first attribute extent failed with " + "error code %i.", vi->i_ino, + (unsigned)le32_to_cpu(ni->type), err); + if (err == -ENOENT) + err = -EIO; + ntfs_attr_reinit_search_ctx(ctx); + if (ntfs_attr_lookup(ni->type, ni->name, ni->name_len, CASE_SENSITIVE, + allocated_size >> vol->cluster_size_bits, NULL, 0, + ctx)) { + ntfs_error(vol->sb, "Failed to find last attribute extent of " + "attribute in error code path. Run chkdsk to " + "recover."); + write_lock_irqsave(&ni->size_lock, flags); + ni->allocated_size = new_alloc_size; + /* + * FIXME: This would fail if @ni is a directory... See above. + * FIXME: The calculation is wrong if we created a hole above. + * For now it does not matter as we never create holes. + */ + if (NInoSparse(ni) || NInoCompressed(ni)) { + ni->itype.compressed.size += new_alloc_size - + allocated_size; + vi->i_blocks = ni->itype.compressed.size >> 9; + } else + vi->i_blocks = new_alloc_size >> 9; + write_unlock_irqrestore(&ni->size_lock, flags); + ntfs_attr_put_search_ctx(ctx); + unmap_mft_record(base_ni); + up_write(&ni->runlist.lock); + /* + * The only thing that is now wrong is the allocated size of the + * base attribute extent which chkdsk should be able to fix. + */ + NVolSetErrors(vol); + return err; + } + ctx->attr->data.non_resident.highest_vcn = cpu_to_sle64( + (allocated_size >> vol->cluster_size_bits) - 1); +undo_alloc: + ll = allocated_size >> vol->cluster_size_bits; + if (ntfs_cluster_free(ni, ll, -1, ctx) < 0) { + ntfs_error(vol->sb, "Failed to release allocated cluster(s) " + "in error code path. Run chkdsk to recover " + "the lost cluster(s)."); + NVolSetErrors(vol); + } + m = ctx->mrec; + a = ctx->attr; + /* + * If the runlist truncation fails and/or the search context is no + * longer valid, we cannot resize the attribute record or build the + * mapping pairs array thus we mark the inode bad so that no access to + * the freed clusters can happen. + */ + if (ntfs_rl_truncate_nolock(vol, &ni->runlist, ll) || IS_ERR(m)) { + ntfs_error(vol->sb, "Failed to %s in error code path. Run " + "chkdsk to recover.", IS_ERR(m) ? + "restore attribute search context" : + "truncate attribute runlist"); + NVolSetErrors(vol); + } else if (mp_rebuilt) { + if (ntfs_attr_record_resize(m, a, attr_len)) { + ntfs_error(vol->sb, "Failed to restore attribute " + "record in error code path. Run " + "chkdsk to recover."); + NVolSetErrors(vol); + } else /* if (success) */ { + if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu( + a->data.non_resident. + mapping_pairs_offset), attr_len - + le16_to_cpu(a->data.non_resident. + mapping_pairs_offset), rl2, ll, -1, + NULL)) { + ntfs_error(vol->sb, "Failed to restore " + "mapping pairs array in error " + "code path. Run chkdsk to " + "recover."); + NVolSetErrors(vol); + } + flush_dcache_mft_record_page(ctx->ntfs_ino); + mark_mft_record_dirty(ctx->ntfs_ino); + } + } +err_out: + if (ctx) + ntfs_attr_put_search_ctx(ctx); + if (m) + unmap_mft_record(base_ni); + up_write(&ni->runlist.lock); +conv_err_out: + ntfs_debug("Failed. Returning error code %i.", err); + return err; +} + +/** + * ntfs_attr_set - fill (a part of) an attribute with a byte + * @ni: ntfs inode describing the attribute to fill + * @ofs: offset inside the attribute at which to start to fill + * @cnt: number of bytes to fill + * @val: the unsigned 8-bit value with which to fill the attribute + * + * Fill @cnt bytes of the attribute described by the ntfs inode @ni starting at + * byte offset @ofs inside the attribute with the constant byte @val. + * + * This function is effectively like memset() applied to an ntfs attribute. + * Note thie function actually only operates on the page cache pages belonging + * to the ntfs attribute and it marks them dirty after doing the memset(). + * Thus it relies on the vm dirty page write code paths to cause the modified + * pages to be written to the mft record/disk. + * + * Return 0 on success and -errno on error. An error code of -ESPIPE means + * that @ofs + @cnt were outside the end of the attribute and no write was + * performed. + */ +int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val) +{ + ntfs_volume *vol = ni->vol; + struct address_space *mapping; + struct page *page; + u8 *kaddr; + pgoff_t idx, end; + unsigned start_ofs, end_ofs, size; + + ntfs_debug("Entering for ofs 0x%llx, cnt 0x%llx, val 0x%hx.", + (long long)ofs, (long long)cnt, val); + BUG_ON(ofs < 0); + BUG_ON(cnt < 0); + if (!cnt) + goto done; + /* + * FIXME: Compressed and encrypted attributes are not supported when + * writing and we should never have gotten here for them. + */ + BUG_ON(NInoCompressed(ni)); + BUG_ON(NInoEncrypted(ni)); + mapping = VFS_I(ni)->i_mapping; + /* Work out the starting index and page offset. */ + idx = ofs >> PAGE_CACHE_SHIFT; + start_ofs = ofs & ~PAGE_CACHE_MASK; + /* Work out the ending index and page offset. */ + end = ofs + cnt; + end_ofs = end & ~PAGE_CACHE_MASK; + /* If the end is outside the inode size return -ESPIPE. */ + if (unlikely(end > i_size_read(VFS_I(ni)))) { + ntfs_error(vol->sb, "Request exceeds end of attribute."); + return -ESPIPE; + } + end >>= PAGE_CACHE_SHIFT; + /* If there is a first partial page, need to do it the slow way. */ + if (start_ofs) { + page = read_mapping_page(mapping, idx, NULL); + if (IS_ERR(page)) { + ntfs_error(vol->sb, "Failed to read first partial " + "page (error, index 0x%lx).", idx); + return PTR_ERR(page); + } + /* + * If the last page is the same as the first page, need to + * limit the write to the end offset. + */ + size = PAGE_CACHE_SIZE; + if (idx == end) + size = end_ofs; + kaddr = kmap_atomic(page); + memset(kaddr + start_ofs, val, size - start_ofs); + flush_dcache_page(page); + kunmap_atomic(kaddr); + set_page_dirty(page); + page_cache_release(page); + balance_dirty_pages_ratelimited(mapping); + cond_resched(); + if (idx == end) + goto done; + idx++; + } + /* Do the whole pages the fast way. */ + for (; idx < end; idx++) { + /* Find or create the current page. (The page is locked.) */ + page = grab_cache_page(mapping, idx); + if (unlikely(!page)) { + ntfs_error(vol->sb, "Insufficient memory to grab " + "page (index 0x%lx).", idx); + return -ENOMEM; + } + kaddr = kmap_atomic(page); + memset(kaddr, val, PAGE_CACHE_SIZE); + flush_dcache_page(page); + kunmap_atomic(kaddr); + /* + * If the page has buffers, mark them uptodate since buffer + * state and not page state is definitive in 2.6 kernels. + */ + if (page_has_buffers(page)) { + struct buffer_head *bh, *head; + + bh = head = page_buffers(page); + do { + set_buffer_uptodate(bh); + } while ((bh = bh->b_this_page) != head); + } + /* Now that buffers are uptodate, set the page uptodate, too. */ + SetPageUptodate(page); + /* + * Set the page and all its buffers dirty and mark the inode + * dirty, too. The VM will write the page later on. + */ + set_page_dirty(page); + /* Finally unlock and release the page. */ + unlock_page(page); + page_cache_release(page); + balance_dirty_pages_ratelimited(mapping); + cond_resched(); + } + /* If there is a last partial page, need to do it the slow way. */ + if (end_ofs) { + page = read_mapping_page(mapping, idx, NULL); + if (IS_ERR(page)) { + ntfs_error(vol->sb, "Failed to read last partial page " + "(error, index 0x%lx).", idx); + return PTR_ERR(page); + } + kaddr = kmap_atomic(page); + memset(kaddr, val, end_ofs); + flush_dcache_page(page); + kunmap_atomic(kaddr); + set_page_dirty(page); + page_cache_release(page); + balance_dirty_pages_ratelimited(mapping); + cond_resched(); + } +done: + ntfs_debug("Done."); + return 0; +} + +#endif /* NTFS_RW */ |