diff options
Diffstat (limited to 'kernel/fs/xfs/xfs_file.c')
| -rw-r--r-- | kernel/fs/xfs/xfs_file.c | 1534 |
1 files changed, 1534 insertions, 0 deletions
diff --git a/kernel/fs/xfs/xfs_file.c b/kernel/fs/xfs/xfs_file.c new file mode 100644 index 000000000..3b7591224 --- /dev/null +++ b/kernel/fs/xfs/xfs_file.c @@ -0,0 +1,1534 @@ +/* + * Copyright (c) 2000-2005 Silicon Graphics, Inc. + * All Rights Reserved. + * + * This program 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. + * + * This program is distributed in the hope that it would 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; if not, write the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ +#include "xfs.h" +#include "xfs_fs.h" +#include "xfs_shared.h" +#include "xfs_format.h" +#include "xfs_log_format.h" +#include "xfs_trans_resv.h" +#include "xfs_mount.h" +#include "xfs_da_format.h" +#include "xfs_da_btree.h" +#include "xfs_inode.h" +#include "xfs_trans.h" +#include "xfs_inode_item.h" +#include "xfs_bmap.h" +#include "xfs_bmap_util.h" +#include "xfs_error.h" +#include "xfs_dir2.h" +#include "xfs_dir2_priv.h" +#include "xfs_ioctl.h" +#include "xfs_trace.h" +#include "xfs_log.h" +#include "xfs_icache.h" +#include "xfs_pnfs.h" + +#include <linux/dcache.h> +#include <linux/falloc.h> +#include <linux/pagevec.h> + +static const struct vm_operations_struct xfs_file_vm_ops; + +/* + * Locking primitives for read and write IO paths to ensure we consistently use + * and order the inode->i_mutex, ip->i_lock and ip->i_iolock. + */ +static inline void +xfs_rw_ilock( + struct xfs_inode *ip, + int type) +{ + if (type & XFS_IOLOCK_EXCL) + mutex_lock(&VFS_I(ip)->i_mutex); + xfs_ilock(ip, type); +} + +static inline void +xfs_rw_iunlock( + struct xfs_inode *ip, + int type) +{ + xfs_iunlock(ip, type); + if (type & XFS_IOLOCK_EXCL) + mutex_unlock(&VFS_I(ip)->i_mutex); +} + +static inline void +xfs_rw_ilock_demote( + struct xfs_inode *ip, + int type) +{ + xfs_ilock_demote(ip, type); + if (type & XFS_IOLOCK_EXCL) + mutex_unlock(&VFS_I(ip)->i_mutex); +} + +/* + * xfs_iozero + * + * xfs_iozero clears the specified range of buffer supplied, + * and marks all the affected blocks as valid and modified. If + * an affected block is not allocated, it will be allocated. If + * an affected block is not completely overwritten, and is not + * valid before the operation, it will be read from disk before + * being partially zeroed. + */ +int +xfs_iozero( + struct xfs_inode *ip, /* inode */ + loff_t pos, /* offset in file */ + size_t count) /* size of data to zero */ +{ + struct page *page; + struct address_space *mapping; + int status; + + mapping = VFS_I(ip)->i_mapping; + do { + unsigned offset, bytes; + void *fsdata; + + offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */ + bytes = PAGE_CACHE_SIZE - offset; + if (bytes > count) + bytes = count; + + status = pagecache_write_begin(NULL, mapping, pos, bytes, + AOP_FLAG_UNINTERRUPTIBLE, + &page, &fsdata); + if (status) + break; + + zero_user(page, offset, bytes); + + status = pagecache_write_end(NULL, mapping, pos, bytes, bytes, + page, fsdata); + WARN_ON(status <= 0); /* can't return less than zero! */ + pos += bytes; + count -= bytes; + status = 0; + } while (count); + + return status; +} + +int +xfs_update_prealloc_flags( + struct xfs_inode *ip, + enum xfs_prealloc_flags flags) +{ + struct xfs_trans *tp; + int error; + + tp = xfs_trans_alloc(ip->i_mount, XFS_TRANS_WRITEID); + error = xfs_trans_reserve(tp, &M_RES(ip->i_mount)->tr_writeid, 0, 0); + if (error) { + xfs_trans_cancel(tp, 0); + return error; + } + + xfs_ilock(ip, XFS_ILOCK_EXCL); + xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL); + + if (!(flags & XFS_PREALLOC_INVISIBLE)) { + ip->i_d.di_mode &= ~S_ISUID; + if (ip->i_d.di_mode & S_IXGRP) + ip->i_d.di_mode &= ~S_ISGID; + xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG); + } + + if (flags & XFS_PREALLOC_SET) + ip->i_d.di_flags |= XFS_DIFLAG_PREALLOC; + if (flags & XFS_PREALLOC_CLEAR) + ip->i_d.di_flags &= ~XFS_DIFLAG_PREALLOC; + + xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); + if (flags & XFS_PREALLOC_SYNC) + xfs_trans_set_sync(tp); + return xfs_trans_commit(tp, 0); +} + +/* + * Fsync operations on directories are much simpler than on regular files, + * as there is no file data to flush, and thus also no need for explicit + * cache flush operations, and there are no non-transaction metadata updates + * on directories either. + */ +STATIC int +xfs_dir_fsync( + struct file *file, + loff_t start, + loff_t end, + int datasync) +{ + struct xfs_inode *ip = XFS_I(file->f_mapping->host); + struct xfs_mount *mp = ip->i_mount; + xfs_lsn_t lsn = 0; + + trace_xfs_dir_fsync(ip); + + xfs_ilock(ip, XFS_ILOCK_SHARED); + if (xfs_ipincount(ip)) + lsn = ip->i_itemp->ili_last_lsn; + xfs_iunlock(ip, XFS_ILOCK_SHARED); + + if (!lsn) + return 0; + return _xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL); +} + +STATIC int +xfs_file_fsync( + struct file *file, + loff_t start, + loff_t end, + int datasync) +{ + struct inode *inode = file->f_mapping->host; + struct xfs_inode *ip = XFS_I(inode); + struct xfs_mount *mp = ip->i_mount; + int error = 0; + int log_flushed = 0; + xfs_lsn_t lsn = 0; + + trace_xfs_file_fsync(ip); + + error = filemap_write_and_wait_range(inode->i_mapping, start, end); + if (error) + return error; + + if (XFS_FORCED_SHUTDOWN(mp)) + return -EIO; + + xfs_iflags_clear(ip, XFS_ITRUNCATED); + + if (mp->m_flags & XFS_MOUNT_BARRIER) { + /* + * If we have an RT and/or log subvolume we need to make sure + * to flush the write cache the device used for file data + * first. This is to ensure newly written file data make + * it to disk before logging the new inode size in case of + * an extending write. + */ + if (XFS_IS_REALTIME_INODE(ip)) + xfs_blkdev_issue_flush(mp->m_rtdev_targp); + else if (mp->m_logdev_targp != mp->m_ddev_targp) + xfs_blkdev_issue_flush(mp->m_ddev_targp); + } + + /* + * All metadata updates are logged, which means that we just have + * to flush the log up to the latest LSN that touched the inode. + */ + xfs_ilock(ip, XFS_ILOCK_SHARED); + if (xfs_ipincount(ip)) { + if (!datasync || + (ip->i_itemp->ili_fields & ~XFS_ILOG_TIMESTAMP)) + lsn = ip->i_itemp->ili_last_lsn; + } + xfs_iunlock(ip, XFS_ILOCK_SHARED); + + if (lsn) + error = _xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, &log_flushed); + + /* + * If we only have a single device, and the log force about was + * a no-op we might have to flush the data device cache here. + * This can only happen for fdatasync/O_DSYNC if we were overwriting + * an already allocated file and thus do not have any metadata to + * commit. + */ + if ((mp->m_flags & XFS_MOUNT_BARRIER) && + mp->m_logdev_targp == mp->m_ddev_targp && + !XFS_IS_REALTIME_INODE(ip) && + !log_flushed) + xfs_blkdev_issue_flush(mp->m_ddev_targp); + + return error; +} + +STATIC ssize_t +xfs_file_read_iter( + struct kiocb *iocb, + struct iov_iter *to) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + struct xfs_inode *ip = XFS_I(inode); + struct xfs_mount *mp = ip->i_mount; + size_t size = iov_iter_count(to); + ssize_t ret = 0; + int ioflags = 0; + xfs_fsize_t n; + loff_t pos = iocb->ki_pos; + + XFS_STATS_INC(xs_read_calls); + + if (unlikely(iocb->ki_flags & IOCB_DIRECT)) + ioflags |= XFS_IO_ISDIRECT; + if (file->f_mode & FMODE_NOCMTIME) + ioflags |= XFS_IO_INVIS; + + if (unlikely(ioflags & XFS_IO_ISDIRECT)) { + xfs_buftarg_t *target = + XFS_IS_REALTIME_INODE(ip) ? + mp->m_rtdev_targp : mp->m_ddev_targp; + /* DIO must be aligned to device logical sector size */ + if ((pos | size) & target->bt_logical_sectormask) { + if (pos == i_size_read(inode)) + return 0; + return -EINVAL; + } + } + + n = mp->m_super->s_maxbytes - pos; + if (n <= 0 || size == 0) + return 0; + + if (n < size) + size = n; + + if (XFS_FORCED_SHUTDOWN(mp)) + return -EIO; + + /* + * Locking is a bit tricky here. If we take an exclusive lock + * for direct IO, we effectively serialise all new concurrent + * read IO to this file and block it behind IO that is currently in + * progress because IO in progress holds the IO lock shared. We only + * need to hold the lock exclusive to blow away the page cache, so + * only take lock exclusively if the page cache needs invalidation. + * This allows the normal direct IO case of no page cache pages to + * proceeed concurrently without serialisation. + */ + xfs_rw_ilock(ip, XFS_IOLOCK_SHARED); + if ((ioflags & XFS_IO_ISDIRECT) && inode->i_mapping->nrpages) { + xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED); + xfs_rw_ilock(ip, XFS_IOLOCK_EXCL); + + if (inode->i_mapping->nrpages) { + ret = filemap_write_and_wait_range( + VFS_I(ip)->i_mapping, + pos, pos + size - 1); + if (ret) { + xfs_rw_iunlock(ip, XFS_IOLOCK_EXCL); + return ret; + } + + /* + * Invalidate whole pages. This can return an error if + * we fail to invalidate a page, but this should never + * happen on XFS. Warn if it does fail. + */ + ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping, + pos >> PAGE_CACHE_SHIFT, + (pos + size - 1) >> PAGE_CACHE_SHIFT); + WARN_ON_ONCE(ret); + ret = 0; + } + xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL); + } + + trace_xfs_file_read(ip, size, pos, ioflags); + + ret = generic_file_read_iter(iocb, to); + if (ret > 0) + XFS_STATS_ADD(xs_read_bytes, ret); + + xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED); + return ret; +} + +STATIC ssize_t +xfs_file_splice_read( + struct file *infilp, + loff_t *ppos, + struct pipe_inode_info *pipe, + size_t count, + unsigned int flags) +{ + struct xfs_inode *ip = XFS_I(infilp->f_mapping->host); + int ioflags = 0; + ssize_t ret; + + XFS_STATS_INC(xs_read_calls); + + if (infilp->f_mode & FMODE_NOCMTIME) + ioflags |= XFS_IO_INVIS; + + if (XFS_FORCED_SHUTDOWN(ip->i_mount)) + return -EIO; + + xfs_rw_ilock(ip, XFS_IOLOCK_SHARED); + + trace_xfs_file_splice_read(ip, count, *ppos, ioflags); + + ret = generic_file_splice_read(infilp, ppos, pipe, count, flags); + if (ret > 0) + XFS_STATS_ADD(xs_read_bytes, ret); + + xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED); + return ret; +} + +/* + * This routine is called to handle zeroing any space in the last block of the + * file that is beyond the EOF. We do this since the size is being increased + * without writing anything to that block and we don't want to read the + * garbage on the disk. + */ +STATIC int /* error (positive) */ +xfs_zero_last_block( + struct xfs_inode *ip, + xfs_fsize_t offset, + xfs_fsize_t isize, + bool *did_zeroing) +{ + struct xfs_mount *mp = ip->i_mount; + xfs_fileoff_t last_fsb = XFS_B_TO_FSBT(mp, isize); + int zero_offset = XFS_B_FSB_OFFSET(mp, isize); + int zero_len; + int nimaps = 1; + int error = 0; + struct xfs_bmbt_irec imap; + + xfs_ilock(ip, XFS_ILOCK_EXCL); + error = xfs_bmapi_read(ip, last_fsb, 1, &imap, &nimaps, 0); + xfs_iunlock(ip, XFS_ILOCK_EXCL); + if (error) + return error; + + ASSERT(nimaps > 0); + + /* + * If the block underlying isize is just a hole, then there + * is nothing to zero. + */ + if (imap.br_startblock == HOLESTARTBLOCK) + return 0; + + zero_len = mp->m_sb.sb_blocksize - zero_offset; + if (isize + zero_len > offset) + zero_len = offset - isize; + *did_zeroing = true; + return xfs_iozero(ip, isize, zero_len); +} + +/* + * Zero any on disk space between the current EOF and the new, larger EOF. + * + * This handles the normal case of zeroing the remainder of the last block in + * the file and the unusual case of zeroing blocks out beyond the size of the + * file. This second case only happens with fixed size extents and when the + * system crashes before the inode size was updated but after blocks were + * allocated. + * + * Expects the iolock to be held exclusive, and will take the ilock internally. + */ +int /* error (positive) */ +xfs_zero_eof( + struct xfs_inode *ip, + xfs_off_t offset, /* starting I/O offset */ + xfs_fsize_t isize, /* current inode size */ + bool *did_zeroing) +{ + struct xfs_mount *mp = ip->i_mount; + xfs_fileoff_t start_zero_fsb; + xfs_fileoff_t end_zero_fsb; + xfs_fileoff_t zero_count_fsb; + xfs_fileoff_t last_fsb; + xfs_fileoff_t zero_off; + xfs_fsize_t zero_len; + int nimaps; + int error = 0; + struct xfs_bmbt_irec imap; + + ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL)); + ASSERT(offset > isize); + + /* + * First handle zeroing the block on which isize resides. + * + * We only zero a part of that block so it is handled specially. + */ + if (XFS_B_FSB_OFFSET(mp, isize) != 0) { + error = xfs_zero_last_block(ip, offset, isize, did_zeroing); + if (error) + return error; + } + + /* + * Calculate the range between the new size and the old where blocks + * needing to be zeroed may exist. + * + * To get the block where the last byte in the file currently resides, + * we need to subtract one from the size and truncate back to a block + * boundary. We subtract 1 in case the size is exactly on a block + * boundary. + */ + last_fsb = isize ? XFS_B_TO_FSBT(mp, isize - 1) : (xfs_fileoff_t)-1; + start_zero_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)isize); + end_zero_fsb = XFS_B_TO_FSBT(mp, offset - 1); + ASSERT((xfs_sfiloff_t)last_fsb < (xfs_sfiloff_t)start_zero_fsb); + if (last_fsb == end_zero_fsb) { + /* + * The size was only incremented on its last block. + * We took care of that above, so just return. + */ + return 0; + } + + ASSERT(start_zero_fsb <= end_zero_fsb); + while (start_zero_fsb <= end_zero_fsb) { + nimaps = 1; + zero_count_fsb = end_zero_fsb - start_zero_fsb + 1; + + xfs_ilock(ip, XFS_ILOCK_EXCL); + error = xfs_bmapi_read(ip, start_zero_fsb, zero_count_fsb, + &imap, &nimaps, 0); + xfs_iunlock(ip, XFS_ILOCK_EXCL); + if (error) + return error; + + ASSERT(nimaps > 0); + + if (imap.br_state == XFS_EXT_UNWRITTEN || + imap.br_startblock == HOLESTARTBLOCK) { + start_zero_fsb = imap.br_startoff + imap.br_blockcount; + ASSERT(start_zero_fsb <= (end_zero_fsb + 1)); + continue; + } + + /* + * There are blocks we need to zero. + */ + zero_off = XFS_FSB_TO_B(mp, start_zero_fsb); + zero_len = XFS_FSB_TO_B(mp, imap.br_blockcount); + + if ((zero_off + zero_len) > offset) + zero_len = offset - zero_off; + + error = xfs_iozero(ip, zero_off, zero_len); + if (error) + return error; + + *did_zeroing = true; + start_zero_fsb = imap.br_startoff + imap.br_blockcount; + ASSERT(start_zero_fsb <= (end_zero_fsb + 1)); + } + + return 0; +} + +/* + * Common pre-write limit and setup checks. + * + * Called with the iolocked held either shared and exclusive according to + * @iolock, and returns with it held. Might upgrade the iolock to exclusive + * if called for a direct write beyond i_size. + */ +STATIC ssize_t +xfs_file_aio_write_checks( + struct kiocb *iocb, + struct iov_iter *from, + int *iolock) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + struct xfs_inode *ip = XFS_I(inode); + ssize_t error = 0; + size_t count = iov_iter_count(from); + +restart: + error = generic_write_checks(iocb, from); + if (error <= 0) + return error; + + error = xfs_break_layouts(inode, iolock, true); + if (error) + return error; + + /* + * If the offset is beyond the size of the file, we need to zero any + * blocks that fall between the existing EOF and the start of this + * write. If zeroing is needed and we are currently holding the + * iolock shared, we need to update it to exclusive which implies + * having to redo all checks before. + * + * We need to serialise against EOF updates that occur in IO + * completions here. We want to make sure that nobody is changing the + * size while we do this check until we have placed an IO barrier (i.e. + * hold the XFS_IOLOCK_EXCL) that prevents new IO from being dispatched. + * The spinlock effectively forms a memory barrier once we have the + * XFS_IOLOCK_EXCL so we are guaranteed to see the latest EOF value + * and hence be able to correctly determine if we need to run zeroing. + */ + spin_lock(&ip->i_flags_lock); + if (iocb->ki_pos > i_size_read(inode)) { + bool zero = false; + + spin_unlock(&ip->i_flags_lock); + if (*iolock == XFS_IOLOCK_SHARED) { + xfs_rw_iunlock(ip, *iolock); + *iolock = XFS_IOLOCK_EXCL; + xfs_rw_ilock(ip, *iolock); + iov_iter_reexpand(from, count); + + /* + * We now have an IO submission barrier in place, but + * AIO can do EOF updates during IO completion and hence + * we now need to wait for all of them to drain. Non-AIO + * DIO will have drained before we are given the + * XFS_IOLOCK_EXCL, and so for most cases this wait is a + * no-op. + */ + inode_dio_wait(inode); + goto restart; + } + error = xfs_zero_eof(ip, iocb->ki_pos, i_size_read(inode), &zero); + if (error) + return error; + } else + spin_unlock(&ip->i_flags_lock); + + /* + * Updating the timestamps will grab the ilock again from + * xfs_fs_dirty_inode, so we have to call it after dropping the + * lock above. Eventually we should look into a way to avoid + * the pointless lock roundtrip. + */ + if (likely(!(file->f_mode & FMODE_NOCMTIME))) { + error = file_update_time(file); + if (error) + return error; + } + + /* + * If we're writing the file then make sure to clear the setuid and + * setgid bits if the process is not being run by root. This keeps + * people from modifying setuid and setgid binaries. + */ + return file_remove_suid(file); +} + +/* + * xfs_file_dio_aio_write - handle direct IO writes + * + * Lock the inode appropriately to prepare for and issue a direct IO write. + * By separating it from the buffered write path we remove all the tricky to + * follow locking changes and looping. + * + * If there are cached pages or we're extending the file, we need IOLOCK_EXCL + * until we're sure the bytes at the new EOF have been zeroed and/or the cached + * pages are flushed out. + * + * In most cases the direct IO writes will be done holding IOLOCK_SHARED + * allowing them to be done in parallel with reads and other direct IO writes. + * However, if the IO is not aligned to filesystem blocks, the direct IO layer + * needs to do sub-block zeroing and that requires serialisation against other + * direct IOs to the same block. In this case we need to serialise the + * submission of the unaligned IOs so that we don't get racing block zeroing in + * the dio layer. To avoid the problem with aio, we also need to wait for + * outstanding IOs to complete so that unwritten extent conversion is completed + * before we try to map the overlapping block. This is currently implemented by + * hitting it with a big hammer (i.e. inode_dio_wait()). + * + * Returns with locks held indicated by @iolock and errors indicated by + * negative return values. + */ +STATIC ssize_t +xfs_file_dio_aio_write( + struct kiocb *iocb, + struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct address_space *mapping = file->f_mapping; + struct inode *inode = mapping->host; + struct xfs_inode *ip = XFS_I(inode); + struct xfs_mount *mp = ip->i_mount; + ssize_t ret = 0; + int unaligned_io = 0; + int iolock; + size_t count = iov_iter_count(from); + loff_t pos = iocb->ki_pos; + loff_t end; + struct iov_iter data; + struct xfs_buftarg *target = XFS_IS_REALTIME_INODE(ip) ? + mp->m_rtdev_targp : mp->m_ddev_targp; + + /* DIO must be aligned to device logical sector size */ + if ((pos | count) & target->bt_logical_sectormask) + return -EINVAL; + + /* "unaligned" here means not aligned to a filesystem block */ + if ((pos & mp->m_blockmask) || ((pos + count) & mp->m_blockmask)) + unaligned_io = 1; + + /* + * We don't need to take an exclusive lock unless there page cache needs + * to be invalidated or unaligned IO is being executed. We don't need to + * consider the EOF extension case here because + * xfs_file_aio_write_checks() will relock the inode as necessary for + * EOF zeroing cases and fill out the new inode size as appropriate. + */ + if (unaligned_io || mapping->nrpages) + iolock = XFS_IOLOCK_EXCL; + else + iolock = XFS_IOLOCK_SHARED; + xfs_rw_ilock(ip, iolock); + + /* + * Recheck if there are cached pages that need invalidate after we got + * the iolock to protect against other threads adding new pages while + * we were waiting for the iolock. + */ + if (mapping->nrpages && iolock == XFS_IOLOCK_SHARED) { + xfs_rw_iunlock(ip, iolock); + iolock = XFS_IOLOCK_EXCL; + xfs_rw_ilock(ip, iolock); + } + + ret = xfs_file_aio_write_checks(iocb, from, &iolock); + if (ret) + goto out; + count = iov_iter_count(from); + pos = iocb->ki_pos; + end = pos + count - 1; + + if (mapping->nrpages) { + ret = filemap_write_and_wait_range(VFS_I(ip)->i_mapping, + pos, end); + if (ret) + goto out; + /* + * Invalidate whole pages. This can return an error if + * we fail to invalidate a page, but this should never + * happen on XFS. Warn if it does fail. + */ + ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping, + pos >> PAGE_CACHE_SHIFT, + end >> PAGE_CACHE_SHIFT); + WARN_ON_ONCE(ret); + ret = 0; + } + + /* + * If we are doing unaligned IO, wait for all other IO to drain, + * otherwise demote the lock if we had to flush cached pages + */ + if (unaligned_io) + inode_dio_wait(inode); + else if (iolock == XFS_IOLOCK_EXCL) { + xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL); + iolock = XFS_IOLOCK_SHARED; + } + + trace_xfs_file_direct_write(ip, count, iocb->ki_pos, 0); + + data = *from; + ret = mapping->a_ops->direct_IO(iocb, &data, pos); + + /* see generic_file_direct_write() for why this is necessary */ + if (mapping->nrpages) { + invalidate_inode_pages2_range(mapping, + pos >> PAGE_CACHE_SHIFT, + end >> PAGE_CACHE_SHIFT); + } + + if (ret > 0) { + pos += ret; + iov_iter_advance(from, ret); + iocb->ki_pos = pos; + } +out: + xfs_rw_iunlock(ip, iolock); + + /* No fallback to buffered IO on errors for XFS. */ + ASSERT(ret < 0 || ret == count); + return ret; +} + +STATIC ssize_t +xfs_file_buffered_aio_write( + struct kiocb *iocb, + struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct address_space *mapping = file->f_mapping; + struct inode *inode = mapping->host; + struct xfs_inode *ip = XFS_I(inode); + ssize_t ret; + int enospc = 0; + int iolock = XFS_IOLOCK_EXCL; + + xfs_rw_ilock(ip, iolock); + + ret = xfs_file_aio_write_checks(iocb, from, &iolock); + if (ret) + goto out; + + /* We can write back this queue in page reclaim */ + current->backing_dev_info = inode_to_bdi(inode); + +write_retry: + trace_xfs_file_buffered_write(ip, iov_iter_count(from), + iocb->ki_pos, 0); + ret = generic_perform_write(file, from, iocb->ki_pos); + if (likely(ret >= 0)) + iocb->ki_pos += ret; + + /* + * If we hit a space limit, try to free up some lingering preallocated + * space before returning an error. In the case of ENOSPC, first try to + * write back all dirty inodes to free up some of the excess reserved + * metadata space. This reduces the chances that the eofblocks scan + * waits on dirty mappings. Since xfs_flush_inodes() is serialized, this + * also behaves as a filter to prevent too many eofblocks scans from + * running at the same time. + */ + if (ret == -EDQUOT && !enospc) { + enospc = xfs_inode_free_quota_eofblocks(ip); + if (enospc) + goto write_retry; + } else if (ret == -ENOSPC && !enospc) { + struct xfs_eofblocks eofb = {0}; + + enospc = 1; + xfs_flush_inodes(ip->i_mount); + eofb.eof_scan_owner = ip->i_ino; /* for locking */ + eofb.eof_flags = XFS_EOF_FLAGS_SYNC; + xfs_icache_free_eofblocks(ip->i_mount, &eofb); + goto write_retry; + } + + current->backing_dev_info = NULL; +out: + xfs_rw_iunlock(ip, iolock); + return ret; +} + +STATIC ssize_t +xfs_file_write_iter( + struct kiocb *iocb, + struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct address_space *mapping = file->f_mapping; + struct inode *inode = mapping->host; + struct xfs_inode *ip = XFS_I(inode); + ssize_t ret; + size_t ocount = iov_iter_count(from); + + XFS_STATS_INC(xs_write_calls); + + if (ocount == 0) + return 0; + + if (XFS_FORCED_SHUTDOWN(ip->i_mount)) + return -EIO; + + if (unlikely(iocb->ki_flags & IOCB_DIRECT)) + ret = xfs_file_dio_aio_write(iocb, from); + else + ret = xfs_file_buffered_aio_write(iocb, from); + + if (ret > 0) { + ssize_t err; + + XFS_STATS_ADD(xs_write_bytes, ret); + + /* Handle various SYNC-type writes */ + err = generic_write_sync(file, iocb->ki_pos - ret, ret); + if (err < 0) + ret = err; + } + return ret; +} + +#define XFS_FALLOC_FL_SUPPORTED \ + (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ + FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE | \ + FALLOC_FL_INSERT_RANGE) + +STATIC long +xfs_file_fallocate( + struct file *file, + int mode, + loff_t offset, + loff_t len) +{ + struct inode *inode = file_inode(file); + struct xfs_inode *ip = XFS_I(inode); + long error; + enum xfs_prealloc_flags flags = 0; + uint iolock = XFS_IOLOCK_EXCL; + loff_t new_size = 0; + bool do_file_insert = 0; + + if (!S_ISREG(inode->i_mode)) + return -EINVAL; + if (mode & ~XFS_FALLOC_FL_SUPPORTED) + return -EOPNOTSUPP; + + xfs_ilock(ip, iolock); + error = xfs_break_layouts(inode, &iolock, false); + if (error) + goto out_unlock; + + xfs_ilock(ip, XFS_MMAPLOCK_EXCL); + iolock |= XFS_MMAPLOCK_EXCL; + + if (mode & FALLOC_FL_PUNCH_HOLE) { + error = xfs_free_file_space(ip, offset, len); + if (error) + goto out_unlock; + } else if (mode & FALLOC_FL_COLLAPSE_RANGE) { + unsigned blksize_mask = (1 << inode->i_blkbits) - 1; + + if (offset & blksize_mask || len & blksize_mask) { + error = -EINVAL; + goto out_unlock; + } + + /* + * There is no need to overlap collapse range with EOF, + * in which case it is effectively a truncate operation + */ + if (offset + len >= i_size_read(inode)) { + error = -EINVAL; + goto out_unlock; + } + + new_size = i_size_read(inode) - len; + + error = xfs_collapse_file_space(ip, offset, len); + if (error) + goto out_unlock; + } else if (mode & FALLOC_FL_INSERT_RANGE) { + unsigned blksize_mask = (1 << inode->i_blkbits) - 1; + + new_size = i_size_read(inode) + len; + if (offset & blksize_mask || len & blksize_mask) { + error = -EINVAL; + goto out_unlock; + } + + /* check the new inode size does not wrap through zero */ + if (new_size > inode->i_sb->s_maxbytes) { + error = -EFBIG; + goto out_unlock; + } + + /* Offset should be less than i_size */ + if (offset >= i_size_read(inode)) { + error = -EINVAL; + goto out_unlock; + } + do_file_insert = 1; + } else { + flags |= XFS_PREALLOC_SET; + + if (!(mode & FALLOC_FL_KEEP_SIZE) && + offset + len > i_size_read(inode)) { + new_size = offset + len; + error = inode_newsize_ok(inode, new_size); + if (error) + goto out_unlock; + } + + if (mode & FALLOC_FL_ZERO_RANGE) + error = xfs_zero_file_space(ip, offset, len); + else + error = xfs_alloc_file_space(ip, offset, len, + XFS_BMAPI_PREALLOC); + if (error) + goto out_unlock; + } + + if (file->f_flags & O_DSYNC) + flags |= XFS_PREALLOC_SYNC; + + error = xfs_update_prealloc_flags(ip, flags); + if (error) + goto out_unlock; + + /* Change file size if needed */ + if (new_size) { + struct iattr iattr; + + iattr.ia_valid = ATTR_SIZE; + iattr.ia_size = new_size; + error = xfs_setattr_size(ip, &iattr); + if (error) + goto out_unlock; + } + + /* + * Perform hole insertion now that the file size has been + * updated so that if we crash during the operation we don't + * leave shifted extents past EOF and hence losing access to + * the data that is contained within them. + */ + if (do_file_insert) + error = xfs_insert_file_space(ip, offset, len); + +out_unlock: + xfs_iunlock(ip, iolock); + return error; +} + + +STATIC int +xfs_file_open( + struct inode *inode, + struct file *file) +{ + if (!(file->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS) + return -EFBIG; + if (XFS_FORCED_SHUTDOWN(XFS_M(inode->i_sb))) + return -EIO; + return 0; +} + +STATIC int +xfs_dir_open( + struct inode *inode, + struct file *file) +{ + struct xfs_inode *ip = XFS_I(inode); + int mode; + int error; + + error = xfs_file_open(inode, file); + if (error) + return error; + + /* + * If there are any blocks, read-ahead block 0 as we're almost + * certain to have the next operation be a read there. + */ + mode = xfs_ilock_data_map_shared(ip); + if (ip->i_d.di_nextents > 0) + xfs_dir3_data_readahead(ip, 0, -1); + xfs_iunlock(ip, mode); + return 0; +} + +STATIC int +xfs_file_release( + struct inode *inode, + struct file *filp) +{ + return xfs_release(XFS_I(inode)); +} + +STATIC int +xfs_file_readdir( + struct file *file, + struct dir_context *ctx) +{ + struct inode *inode = file_inode(file); + xfs_inode_t *ip = XFS_I(inode); + size_t bufsize; + + /* + * The Linux API doesn't pass down the total size of the buffer + * we read into down to the filesystem. With the filldir concept + * it's not needed for correct information, but the XFS dir2 leaf + * code wants an estimate of the buffer size to calculate it's + * readahead window and size the buffers used for mapping to + * physical blocks. + * + * Try to give it an estimate that's good enough, maybe at some + * point we can change the ->readdir prototype to include the + * buffer size. For now we use the current glibc buffer size. + */ + bufsize = (size_t)min_t(loff_t, 32768, ip->i_d.di_size); + + return xfs_readdir(ip, ctx, bufsize); +} + +STATIC int +xfs_file_mmap( + struct file *filp, + struct vm_area_struct *vma) +{ + vma->vm_ops = &xfs_file_vm_ops; + + file_accessed(filp); + return 0; +} + +/* + * This type is designed to indicate the type of offset we would like + * to search from page cache for xfs_seek_hole_data(). + */ +enum { + HOLE_OFF = 0, + DATA_OFF, +}; + +/* + * Lookup the desired type of offset from the given page. + * + * On success, return true and the offset argument will point to the + * start of the region that was found. Otherwise this function will + * return false and keep the offset argument unchanged. + */ +STATIC bool +xfs_lookup_buffer_offset( + struct page *page, + loff_t *offset, + unsigned int type) +{ + loff_t lastoff = page_offset(page); + bool found = false; + struct buffer_head *bh, *head; + + bh = head = page_buffers(page); + do { + /* + * Unwritten extents that have data in the page + * cache covering them can be identified by the + * BH_Unwritten state flag. Pages with multiple + * buffers might have a mix of holes, data and + * unwritten extents - any buffer with valid + * data in it should have BH_Uptodate flag set + * on it. + */ + if (buffer_unwritten(bh) || + buffer_uptodate(bh)) { + if (type == DATA_OFF) + found = true; + } else { + if (type == HOLE_OFF) + found = true; + } + + if (found) { + *offset = lastoff; + break; + } + lastoff += bh->b_size; + } while ((bh = bh->b_this_page) != head); + + return found; +} + +/* + * This routine is called to find out and return a data or hole offset + * from the page cache for unwritten extents according to the desired + * type for xfs_seek_hole_data(). + * + * The argument offset is used to tell where we start to search from the + * page cache. Map is used to figure out the end points of the range to + * lookup pages. + * + * Return true if the desired type of offset was found, and the argument + * offset is filled with that address. Otherwise, return false and keep + * offset unchanged. + */ +STATIC bool +xfs_find_get_desired_pgoff( + struct inode *inode, + struct xfs_bmbt_irec *map, + unsigned int type, + loff_t *offset) +{ + struct xfs_inode *ip = XFS_I(inode); + struct xfs_mount *mp = ip->i_mount; + struct pagevec pvec; + pgoff_t index; + pgoff_t end; + loff_t endoff; + loff_t startoff = *offset; + loff_t lastoff = startoff; + bool found = false; + + pagevec_init(&pvec, 0); + + index = startoff >> PAGE_CACHE_SHIFT; + endoff = XFS_FSB_TO_B(mp, map->br_startoff + map->br_blockcount); + end = endoff >> PAGE_CACHE_SHIFT; + do { + int want; + unsigned nr_pages; + unsigned int i; + + want = min_t(pgoff_t, end - index, PAGEVEC_SIZE); + nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index, + want); + /* + * No page mapped into given range. If we are searching holes + * and if this is the first time we got into the loop, it means + * that the given offset is landed in a hole, return it. + * + * If we have already stepped through some block buffers to find + * holes but they all contains data. In this case, the last + * offset is already updated and pointed to the end of the last + * mapped page, if it does not reach the endpoint to search, + * that means there should be a hole between them. + */ + if (nr_pages == 0) { + /* Data search found nothing */ + if (type == DATA_OFF) + break; + + ASSERT(type == HOLE_OFF); + if (lastoff == startoff || lastoff < endoff) { + found = true; + *offset = lastoff; + } + break; + } + + /* + * At lease we found one page. If this is the first time we + * step into the loop, and if the first page index offset is + * greater than the given search offset, a hole was found. + */ + if (type == HOLE_OFF && lastoff == startoff && + lastoff < page_offset(pvec.pages[0])) { + found = true; + break; + } + + for (i = 0; i < nr_pages; i++) { + struct page *page = pvec.pages[i]; + loff_t b_offset; + + /* + * At this point, the page may be truncated or + * invalidated (changing page->mapping to NULL), + * or even swizzled back from swapper_space to tmpfs + * file mapping. However, page->index will not change + * because we have a reference on the page. + * + * Searching done if the page index is out of range. + * If the current offset is not reaches the end of + * the specified search range, there should be a hole + * between them. + */ + if (page->index > end) { + if (type == HOLE_OFF && lastoff < endoff) { + *offset = lastoff; + found = true; + } + goto out; + } + + lock_page(page); + /* + * Page truncated or invalidated(page->mapping == NULL). + * We can freely skip it and proceed to check the next + * page. + */ + if (unlikely(page->mapping != inode->i_mapping)) { + unlock_page(page); + continue; + } + + if (!page_has_buffers(page)) { + unlock_page(page); + continue; + } + + found = xfs_lookup_buffer_offset(page, &b_offset, type); + if (found) { + /* + * The found offset may be less than the start + * point to search if this is the first time to + * come here. + */ + *offset = max_t(loff_t, startoff, b_offset); + unlock_page(page); + goto out; + } + + /* + * We either searching data but nothing was found, or + * searching hole but found a data buffer. In either + * case, probably the next page contains the desired + * things, update the last offset to it so. + */ + lastoff = page_offset(page) + PAGE_SIZE; + unlock_page(page); + } + + /* + * The number of returned pages less than our desired, search + * done. In this case, nothing was found for searching data, + * but we found a hole behind the last offset. + */ + if (nr_pages < want) { + if (type == HOLE_OFF) { + *offset = lastoff; + found = true; + } + break; + } + + index = pvec.pages[i - 1]->index + 1; + pagevec_release(&pvec); + } while (index <= end); + +out: + pagevec_release(&pvec); + return found; +} + +STATIC loff_t +xfs_seek_hole_data( + struct file *file, + loff_t start, + int whence) +{ + struct inode *inode = file->f_mapping->host; + struct xfs_inode *ip = XFS_I(inode); + struct xfs_mount *mp = ip->i_mount; + loff_t uninitialized_var(offset); + xfs_fsize_t isize; + xfs_fileoff_t fsbno; + xfs_filblks_t end; + uint lock; + int error; + + if (XFS_FORCED_SHUTDOWN(mp)) + return -EIO; + + lock = xfs_ilock_data_map_shared(ip); + + isize = i_size_read(inode); + if (start >= isize) { + error = -ENXIO; + goto out_unlock; + } + + /* + * Try to read extents from the first block indicated + * by fsbno to the end block of the file. + */ + fsbno = XFS_B_TO_FSBT(mp, start); + end = XFS_B_TO_FSB(mp, isize); + + for (;;) { + struct xfs_bmbt_irec map[2]; + int nmap = 2; + unsigned int i; + + error = xfs_bmapi_read(ip, fsbno, end - fsbno, map, &nmap, + XFS_BMAPI_ENTIRE); + if (error) + goto out_unlock; + + /* No extents at given offset, must be beyond EOF */ + if (nmap == 0) { + error = -ENXIO; + goto out_unlock; + } + + for (i = 0; i < nmap; i++) { + offset = max_t(loff_t, start, + XFS_FSB_TO_B(mp, map[i].br_startoff)); + + /* Landed in the hole we wanted? */ + if (whence == SEEK_HOLE && + map[i].br_startblock == HOLESTARTBLOCK) + goto out; + + /* Landed in the data extent we wanted? */ + if (whence == SEEK_DATA && + (map[i].br_startblock == DELAYSTARTBLOCK || + (map[i].br_state == XFS_EXT_NORM && + !isnullstartblock(map[i].br_startblock)))) + goto out; + + /* + * Landed in an unwritten extent, try to search + * for hole or data from page cache. + */ + if (map[i].br_state == XFS_EXT_UNWRITTEN) { + if (xfs_find_get_desired_pgoff(inode, &map[i], + whence == SEEK_HOLE ? HOLE_OFF : DATA_OFF, + &offset)) + goto out; + } + } + + /* + * We only received one extent out of the two requested. This + * means we've hit EOF and didn't find what we are looking for. + */ + if (nmap == 1) { + /* + * If we were looking for a hole, set offset to + * the end of the file (i.e., there is an implicit + * hole at the end of any file). + */ + if (whence == SEEK_HOLE) { + offset = isize; + break; + } + /* + * If we were looking for data, it's nowhere to be found + */ + ASSERT(whence == SEEK_DATA); + error = -ENXIO; + goto out_unlock; + } + + ASSERT(i > 1); + + /* + * Nothing was found, proceed to the next round of search + * if the next reading offset is not at or beyond EOF. + */ + fsbno = map[i - 1].br_startoff + map[i - 1].br_blockcount; + start = XFS_FSB_TO_B(mp, fsbno); + if (start >= isize) { + if (whence == SEEK_HOLE) { + offset = isize; + break; + } + ASSERT(whence == SEEK_DATA); + error = -ENXIO; + goto out_unlock; + } + } + +out: + /* + * If at this point we have found the hole we wanted, the returned + * offset may be bigger than the file size as it may be aligned to + * page boundary for unwritten extents. We need to deal with this + * situation in particular. + */ + if (whence == SEEK_HOLE) + offset = min_t(loff_t, offset, isize); + offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes); + +out_unlock: + xfs_iunlock(ip, lock); + + if (error) + return error; + return offset; +} + +STATIC loff_t +xfs_file_llseek( + struct file *file, + loff_t offset, + int whence) +{ + switch (whence) { + case SEEK_END: + case SEEK_CUR: + case SEEK_SET: + return generic_file_llseek(file, offset, whence); + case SEEK_HOLE: + case SEEK_DATA: + return xfs_seek_hole_data(file, offset, whence); + default: + return -EINVAL; + } +} + +/* + * Locking for serialisation of IO during page faults. This results in a lock + * ordering of: + * + * mmap_sem (MM) + * i_mmap_lock (XFS - truncate serialisation) + * page_lock (MM) + * i_lock (XFS - extent map serialisation) + */ +STATIC int +xfs_filemap_fault( + struct vm_area_struct *vma, + struct vm_fault *vmf) +{ + struct xfs_inode *ip = XFS_I(vma->vm_file->f_mapping->host); + int error; + + trace_xfs_filemap_fault(ip); + + xfs_ilock(ip, XFS_MMAPLOCK_SHARED); + error = filemap_fault(vma, vmf); + xfs_iunlock(ip, XFS_MMAPLOCK_SHARED); + + return error; +} + +/* + * mmap()d file has taken write protection fault and is being made writable. We + * can set the page state up correctly for a writable page, which means we can + * do correct delalloc accounting (ENOSPC checking!) and unwritten extent + * mapping. + */ +STATIC int +xfs_filemap_page_mkwrite( + struct vm_area_struct *vma, + struct vm_fault *vmf) +{ + struct xfs_inode *ip = XFS_I(vma->vm_file->f_mapping->host); + int error; + + trace_xfs_filemap_page_mkwrite(ip); + + xfs_ilock(ip, XFS_MMAPLOCK_SHARED); + error = block_page_mkwrite(vma, vmf, xfs_get_blocks); + xfs_iunlock(ip, XFS_MMAPLOCK_SHARED); + + return error; +} + +const struct file_operations xfs_file_operations = { + .llseek = xfs_file_llseek, + .read_iter = xfs_file_read_iter, + .write_iter = xfs_file_write_iter, + .splice_read = xfs_file_splice_read, + .splice_write = iter_file_splice_write, + .unlocked_ioctl = xfs_file_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = xfs_file_compat_ioctl, +#endif + .mmap = xfs_file_mmap, + .open = xfs_file_open, + .release = xfs_file_release, + .fsync = xfs_file_fsync, + .fallocate = xfs_file_fallocate, +}; + +const struct file_operations xfs_dir_file_operations = { + .open = xfs_dir_open, + .read = generic_read_dir, + .iterate = xfs_file_readdir, + .llseek = generic_file_llseek, + .unlocked_ioctl = xfs_file_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = xfs_file_compat_ioctl, +#endif + .fsync = xfs_dir_fsync, +}; + +static const struct vm_operations_struct xfs_file_vm_ops = { + .fault = xfs_filemap_fault, + .map_pages = filemap_map_pages, + .page_mkwrite = xfs_filemap_page_mkwrite, +}; |