/* * 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 #include #include #include 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 clears the specified range supplied via the page cache (except in * the DAX case). Writes through the page cache will allocate blocks over holes, * though the callers usually map the holes first and avoid them. If a block is * not completely zeroed, then it will be read from disk before being partially * zeroed. * * In the DAX case, we can just directly write to the underlying pages. This * will not allocate blocks, but will avoid holes and unwritten extents and so * not do unnecessary work. */ 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 = 0; 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; if (IS_DAX(VFS_I(ip))) { status = dax_zero_page_range(VFS_I(ip), pos, bytes, xfs_get_blocks_direct); if (status) break; } else { 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! */ status = 0; } pos += bytes; count -= bytes; } 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); 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); } /* * 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 ((ioflags & XFS_IO_ISDIRECT) && !IS_DAX(inode)) { 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); /* * The generic dio code only flushes the range of the particular * I/O. Because we take an exclusive lock here, this whole * sequence is considerably more expensive for us. This has a * noticeable performance impact for any file with cached pages, * even when outside of the range of the particular I/O. * * Hence, amortize the cost of the lock against a full file * flush and reduce the chances of repeated iolock cycles going * forward. */ if (inode->i_mapping->nrpages) { ret = filemap_write_and_wait(VFS_I(ip)->i_mapping); 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(VFS_I(ip)->i_mapping); 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); /* for dax, we need to avoid the page cache */ if (IS_DAX(VFS_I(ip))) ret = default_file_splice_read(infilp, ppos, pipe, count, flags); else 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; /* For changing security info in file_remove_privs() we need i_mutex */ if (*iolock == XFS_IOLOCK_SHARED && !IS_NOSEC(inode)) { xfs_rw_iunlock(ip, *iolock); *iolock = XFS_IOLOCK_EXCL; xfs_rw_ilock(ip, *iolock); goto restart; } /* * 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. */ if (!IS_NOSEC(inode)) return file_remove_privs(file); return 0; } /* * 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 (!IS_DAX(inode) && ((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; /* * See xfs_file_read_iter() for why we do a full-file flush here. */ if (mapping->nrpages) { ret = filemap_write_and_wait(VFS_I(ip)->i_mapping); 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(VFS_I(ip)->i_mapping); 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. DAX can result in * partial writes, but direct IO will either complete fully or fail. */ ASSERT(ret < 0 || ret == count || IS_DAX(VFS_I(ip))); 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 ((iocb->ki_flags & IOCB_DIRECT) || IS_DAX(inode)) 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); } /* * 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) * sb_start_pagefault(vfs, freeze) * i_mmap_lock (XFS - truncate serialisation) * page_lock (MM) * i_lock (XFS - extent map serialisation) */ /* * 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 inode *inode = file_inode(vma->vm_file); int ret; trace_xfs_filemap_page_mkwrite(XFS_I(inode)); sb_start_pagefault(inode->i_sb); file_update_time(vma->vm_file); xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); if (IS_DAX(inode)) { ret = __dax_mkwrite(vma, vmf, xfs_get_blocks_dax_fault, NULL); } else { ret = __block_page_mkwrite(vma, vmf, xfs_get_blocks); ret = block_page_mkwrite_return(ret); } xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); sb_end_pagefault(inode->i_sb); return ret; } STATIC int xfs_filemap_fault( struct vm_area_struct *vma, struct vm_fault *vmf) { struct inode *inode = file_inode(vma->vm_file); int ret; trace_xfs_filemap_fault(XFS_I(inode)); /* DAX can shortcut the normal fault path on write faults! */ if ((vmf->flags & FAULT_FLAG_WRITE) && IS_DAX(inode)) return xfs_filemap_page_mkwrite(vma, vmf); xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); if (IS_DAX(inode)) { /* * we do not want to trigger unwritten extent conversion on read * faults - that is unnecessary overhead and would also require * changes to xfs_get_blocks_direct() to map unwritten extent * ioend for conversion on read-only mappings. */ ret = __dax_fault(vma, vmf, xfs_get_blocks_dax_fault, NULL); } else ret = filemap_fault(vma, vmf); xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); return ret; } STATIC int xfs_filemap_pmd_fault( struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, unsigned int flags) { struct inode *inode = file_inode(vma->vm_file); struct xfs_inode *ip = XFS_I(inode); int ret; if (!IS_DAX(inode)) return VM_FAULT_FALLBACK; trace_xfs_filemap_pmd_fault(ip); sb_start_pagefault(inode->i_sb); file_update_time(vma->vm_file); xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); ret = __dax_pmd_fault(vma, addr, pmd, flags, xfs_get_blocks_dax_fault, NULL); xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); sb_end_pagefault(inode->i_sb); return ret; } /* * pfn_mkwrite was originally inteneded to ensure we capture time stamp * updates on write faults. In reality, it's need to serialise against * truncate similar to page_mkwrite. Hence we open-code dax_pfn_mkwrite() * here and cycle the XFS_MMAPLOCK_SHARED to ensure we serialise the fault * barrier in place. */ static int xfs_filemap_pfn_mkwrite( struct vm_area_struct *vma, struct vm_fault *vmf) { struct inode *inode = file_inode(vma->vm_file); struct xfs_inode *ip = XFS_I(inode); int ret = VM_FAULT_NOPAGE; loff_t size; trace_xfs_filemap_pfn_mkwrite(ip); sb_start_pagefault(inode->i_sb); file_update_time(vma->vm_file); /* check if the faulting page hasn't raced with truncate */ xfs_ilock(ip, XFS_MMAPLOCK_SHARED); size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; if (vmf->pgoff >= size) ret = VM_FAULT_SIGBUS; xfs_iunlock(ip, XFS_MMAPLOCK_SHARED); sb_end_pagefault(inode->i_sb); return ret; } static const struct vm_operations_struct xfs_file_vm_ops = { .fault = xfs_filemap_fault, .pmd_fault = xfs_filemap_pmd_fault, .map_pages = filemap_map_pages, .page_mkwrite = xfs_filemap_page_mkwrite, .pfn_mkwrite = xfs_filemap_pfn_mkwrite, }; STATIC int xfs_file_mmap( struct file *filp, struct vm_area_struct *vma) { file_accessed(filp); vma->vm_ops = &xfs_file_vm_ops; if (IS_DAX(file_inode(filp))) vma->vm_flags |= VM_MIXEDMAP | VM_HUGEPAGE; return 0; } 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, };