summaryrefslogtreecommitdiffstats
path: root/fs/xfs/xfs_file.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/xfs/xfs_file.c')
-rw-r--r--fs/xfs/xfs_file.c1096
1 files changed, 1096 insertions, 0 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
new file mode 100644
index 00000000000..7f7b42469ea
--- /dev/null
+++ b/fs/xfs/xfs_file.c
@@ -0,0 +1,1096 @@
+/*
+ * 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_bit.h"
+#include "xfs_log.h"
+#include "xfs_inum.h"
+#include "xfs_sb.h"
+#include "xfs_ag.h"
+#include "xfs_trans.h"
+#include "xfs_mount.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_alloc.h"
+#include "xfs_dinode.h"
+#include "xfs_inode.h"
+#include "xfs_inode_item.h"
+#include "xfs_bmap.h"
+#include "xfs_error.h"
+#include "xfs_vnodeops.h"
+#include "xfs_da_btree.h"
+#include "xfs_ioctl.h"
+#include "xfs_trace.h"
+
+#include <linux/dcache.h>
+#include <linux/falloc.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.
+ */
+STATIC 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);
+}
+
+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;
+ struct xfs_trans *tp;
+ int error = 0;
+ int log_flushed = 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 -XFS_ERROR(EIO);
+
+ xfs_iflags_clear(ip, XFS_ITRUNCATED);
+
+ xfs_ilock(ip, XFS_IOLOCK_SHARED);
+ xfs_ioend_wait(ip);
+ xfs_iunlock(ip, XFS_IOLOCK_SHARED);
+
+ 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);
+ }
+
+ /*
+ * We always need to make sure that the required inode state is safe on
+ * disk. The inode might be clean but we still might need to force the
+ * log because of committed transactions that haven't hit the disk yet.
+ * Likewise, there could be unflushed non-transactional changes to the
+ * inode core that have to go to disk and this requires us to issue
+ * a synchronous transaction to capture these changes correctly.
+ *
+ * This code relies on the assumption that if the i_update_core field
+ * of the inode is clear and the inode is unpinned then it is clean
+ * and no action is required.
+ */
+ xfs_ilock(ip, XFS_ILOCK_SHARED);
+
+ /*
+ * First check if the VFS inode is marked dirty. All the dirtying
+ * of non-transactional updates no goes through mark_inode_dirty*,
+ * which allows us to distinguish beteeen pure timestamp updates
+ * and i_size updates which need to be caught for fdatasync.
+ * After that also theck for the dirty state in the XFS inode, which
+ * might gets cleared when the inode gets written out via the AIL
+ * or xfs_iflush_cluster.
+ */
+ if (((inode->i_state & I_DIRTY_DATASYNC) ||
+ ((inode->i_state & I_DIRTY_SYNC) && !datasync)) &&
+ ip->i_update_core) {
+ /*
+ * Kick off a transaction to log the inode core to get the
+ * updates. The sync transaction will also force the log.
+ */
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
+ tp = xfs_trans_alloc(mp, XFS_TRANS_FSYNC_TS);
+ error = xfs_trans_reserve(tp, 0,
+ XFS_FSYNC_TS_LOG_RES(mp), 0, 0, 0);
+ if (error) {
+ xfs_trans_cancel(tp, 0);
+ return -error;
+ }
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+
+ /*
+ * Note - it's possible that we might have pushed ourselves out
+ * of the way during trans_reserve which would flush the inode.
+ * But there's no guarantee that the inode buffer has actually
+ * gone out yet (it's delwri). Plus the buffer could be pinned
+ * anyway if it's part of an inode in another recent
+ * transaction. So we play it safe and fire off the
+ * transaction anyway.
+ */
+ xfs_trans_ijoin(tp, ip);
+ xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+ xfs_trans_set_sync(tp);
+ error = _xfs_trans_commit(tp, 0, &log_flushed);
+
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+ } else {
+ /*
+ * Timestamps/size haven't changed since last inode flush or
+ * inode transaction commit. That means either nothing got
+ * written or a transaction committed which caught the updates.
+ * If the latter happened and the transaction hasn't hit the
+ * disk yet, the inode will be still be pinned. If it is,
+ * force the log.
+ */
+ if (xfs_ipincount(ip)) {
+ error = _xfs_log_force_lsn(mp,
+ ip->i_itemp->ili_last_lsn,
+ XFS_LOG_SYNC, &log_flushed);
+ }
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
+ }
+
+ /*
+ * 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_aio_read(
+ struct kiocb *iocb,
+ const struct iovec *iovp,
+ unsigned long nr_segs,
+ loff_t pos)
+{
+ 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 = 0;
+ ssize_t ret = 0;
+ int ioflags = 0;
+ xfs_fsize_t n;
+ unsigned long seg;
+
+ XFS_STATS_INC(xs_read_calls);
+
+ BUG_ON(iocb->ki_pos != pos);
+
+ if (unlikely(file->f_flags & O_DIRECT))
+ ioflags |= IO_ISDIRECT;
+ if (file->f_mode & FMODE_NOCMTIME)
+ ioflags |= IO_INVIS;
+
+ /* START copy & waste from filemap.c */
+ for (seg = 0; seg < nr_segs; seg++) {
+ const struct iovec *iv = &iovp[seg];
+
+ /*
+ * If any segment has a negative length, or the cumulative
+ * length ever wraps negative then return -EINVAL.
+ */
+ size += iv->iov_len;
+ if (unlikely((ssize_t)(size|iv->iov_len) < 0))
+ return XFS_ERROR(-EINVAL);
+ }
+ /* END copy & waste from filemap.c */
+
+ if (unlikely(ioflags & IO_ISDIRECT)) {
+ xfs_buftarg_t *target =
+ XFS_IS_REALTIME_INODE(ip) ?
+ mp->m_rtdev_targp : mp->m_ddev_targp;
+ if ((iocb->ki_pos & target->bt_smask) ||
+ (size & target->bt_smask)) {
+ if (iocb->ki_pos == ip->i_size)
+ return 0;
+ return -XFS_ERROR(EINVAL);
+ }
+ }
+
+ n = XFS_MAXIOFFSET(mp) - iocb->ki_pos;
+ if (n <= 0 || size == 0)
+ return 0;
+
+ if (n < size)
+ size = n;
+
+ if (XFS_FORCED_SHUTDOWN(mp))
+ return -EIO;
+
+ if (unlikely(ioflags & IO_ISDIRECT)) {
+ xfs_rw_ilock(ip, XFS_IOLOCK_EXCL);
+
+ if (inode->i_mapping->nrpages) {
+ ret = -xfs_flushinval_pages(ip,
+ (iocb->ki_pos & PAGE_CACHE_MASK),
+ -1, FI_REMAPF_LOCKED);
+ if (ret) {
+ xfs_rw_iunlock(ip, XFS_IOLOCK_EXCL);
+ return ret;
+ }
+ }
+ xfs_rw_ilock_demote(ip, XFS_IOLOCK_EXCL);
+ } else
+ xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
+
+ trace_xfs_file_read(ip, size, iocb->ki_pos, ioflags);
+
+ ret = generic_file_aio_read(iocb, iovp, nr_segs, iocb->ki_pos);
+ 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 |= 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;
+}
+
+STATIC void
+xfs_aio_write_isize_update(
+ struct inode *inode,
+ loff_t *ppos,
+ ssize_t bytes_written)
+{
+ struct xfs_inode *ip = XFS_I(inode);
+ xfs_fsize_t isize = i_size_read(inode);
+
+ if (bytes_written > 0)
+ XFS_STATS_ADD(xs_write_bytes, bytes_written);
+
+ if (unlikely(bytes_written < 0 && bytes_written != -EFAULT &&
+ *ppos > isize))
+ *ppos = isize;
+
+ if (*ppos > ip->i_size) {
+ xfs_rw_ilock(ip, XFS_ILOCK_EXCL);
+ if (*ppos > ip->i_size)
+ ip->i_size = *ppos;
+ xfs_rw_iunlock(ip, XFS_ILOCK_EXCL);
+ }
+}
+
+/*
+ * If this was a direct or synchronous I/O that failed (such as ENOSPC) then
+ * part of the I/O may have been written to disk before the error occurred. In
+ * this case the on-disk file size may have been adjusted beyond the in-memory
+ * file size and now needs to be truncated back.
+ */
+STATIC void
+xfs_aio_write_newsize_update(
+ struct xfs_inode *ip)
+{
+ if (ip->i_new_size) {
+ xfs_rw_ilock(ip, XFS_ILOCK_EXCL);
+ ip->i_new_size = 0;
+ if (ip->i_d.di_size > ip->i_size)
+ ip->i_d.di_size = ip->i_size;
+ xfs_rw_iunlock(ip, XFS_ILOCK_EXCL);
+ }
+}
+
+/*
+ * xfs_file_splice_write() does not use xfs_rw_ilock() because
+ * generic_file_splice_write() takes the i_mutex itself. This, in theory,
+ * couuld cause lock inversions between the aio_write path and the splice path
+ * if someone is doing concurrent splice(2) based writes and write(2) based
+ * writes to the same inode. The only real way to fix this is to re-implement
+ * the generic code here with correct locking orders.
+ */
+STATIC ssize_t
+xfs_file_splice_write(
+ struct pipe_inode_info *pipe,
+ struct file *outfilp,
+ loff_t *ppos,
+ size_t count,
+ unsigned int flags)
+{
+ struct inode *inode = outfilp->f_mapping->host;
+ struct xfs_inode *ip = XFS_I(inode);
+ xfs_fsize_t new_size;
+ int ioflags = 0;
+ ssize_t ret;
+
+ XFS_STATS_INC(xs_write_calls);
+
+ if (outfilp->f_mode & FMODE_NOCMTIME)
+ ioflags |= IO_INVIS;
+
+ if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+ return -EIO;
+
+ xfs_ilock(ip, XFS_IOLOCK_EXCL);
+
+ new_size = *ppos + count;
+
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ if (new_size > ip->i_size)
+ ip->i_new_size = new_size;
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+ trace_xfs_file_splice_write(ip, count, *ppos, ioflags);
+
+ ret = generic_file_splice_write(pipe, outfilp, ppos, count, flags);
+
+ xfs_aio_write_isize_update(inode, ppos, ret);
+ xfs_aio_write_newsize_update(ip);
+ xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+ 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 anyone to read the garbage on the disk.
+ */
+STATIC int /* error (positive) */
+xfs_zero_last_block(
+ xfs_inode_t *ip,
+ xfs_fsize_t offset,
+ xfs_fsize_t isize)
+{
+ xfs_fileoff_t last_fsb;
+ xfs_mount_t *mp = ip->i_mount;
+ int nimaps;
+ int zero_offset;
+ int zero_len;
+ int error = 0;
+ xfs_bmbt_irec_t imap;
+
+ ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+
+ zero_offset = XFS_B_FSB_OFFSET(mp, isize);
+ if (zero_offset == 0) {
+ /*
+ * There are no extra bytes in the last block on disk to
+ * zero, so return.
+ */
+ return 0;
+ }
+
+ last_fsb = XFS_B_TO_FSBT(mp, isize);
+ nimaps = 1;
+ error = xfs_bmapi(NULL, ip, last_fsb, 1, 0, NULL, 0, &imap,
+ &nimaps, NULL);
+ 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 the part of the last block beyond the EOF, and write it
+ * out sync. We need to drop the ilock while we do this so we
+ * don't deadlock when the buffer cache calls back to us.
+ */
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+ zero_len = mp->m_sb.sb_blocksize - zero_offset;
+ if (isize + zero_len > offset)
+ zero_len = offset - isize;
+ error = xfs_iozero(ip, isize, zero_len);
+
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ ASSERT(error >= 0);
+ return error;
+}
+
+/*
+ * 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. If fill is set,
+ * then any holes in the range are filled and zeroed. If not, the holes
+ * are left alone as holes.
+ */
+
+int /* error (positive) */
+xfs_zero_eof(
+ xfs_inode_t *ip,
+ xfs_off_t offset, /* starting I/O offset */
+ xfs_fsize_t isize) /* current inode size */
+{
+ xfs_mount_t *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;
+ xfs_bmbt_irec_t imap;
+
+ ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|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.
+ */
+ error = xfs_zero_last_block(ip, offset, isize);
+ if (error) {
+ ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
+ 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;
+ error = xfs_bmapi(NULL, ip, start_zero_fsb, zero_count_fsb,
+ 0, NULL, 0, &imap, &nimaps, NULL);
+ if (error) {
+ ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_IOLOCK_EXCL));
+ return error;
+ }
+ ASSERT(nimaps > 0);
+
+ if (imap.br_state == XFS_EXT_UNWRITTEN ||
+ imap.br_startblock == HOLESTARTBLOCK) {
+ /*
+ * This loop handles initializing pages that were
+ * partially initialized by the code below this
+ * loop. It basically zeroes the part of the page
+ * that sits on a hole and sets the page as P_HOLE
+ * and calls remapf if it is a mapped file.
+ */
+ 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.
+ * Drop the inode lock while we're doing the I/O.
+ * We'll still have the iolock to protect us.
+ */
+ xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+ 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) {
+ goto out_lock;
+ }
+
+ start_zero_fsb = imap.br_startoff + imap.br_blockcount;
+ ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
+
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ }
+
+ return 0;
+
+out_lock:
+ xfs_ilock(ip, XFS_ILOCK_EXCL);
+ ASSERT(error >= 0);
+ return error;
+}
+
+/*
+ * Common pre-write limit and setup checks.
+ *
+ * Returns with iolock held according to @iolock.
+ */
+STATIC ssize_t
+xfs_file_aio_write_checks(
+ struct file *file,
+ loff_t *pos,
+ size_t *count,
+ int *iolock)
+{
+ struct inode *inode = file->f_mapping->host;
+ struct xfs_inode *ip = XFS_I(inode);
+ xfs_fsize_t new_size;
+ int error = 0;
+
+ error = generic_write_checks(file, pos, count, S_ISBLK(inode->i_mode));
+ if (error) {
+ xfs_rw_iunlock(ip, XFS_ILOCK_EXCL | *iolock);
+ *iolock = 0;
+ return error;
+ }
+
+ new_size = *pos + *count;
+ if (new_size > ip->i_size)
+ ip->i_new_size = new_size;
+
+ if (likely(!(file->f_mode & FMODE_NOCMTIME)))
+ file_update_time(file);
+
+ /*
+ * 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 (*pos > ip->i_size)
+ error = -xfs_zero_eof(ip, *pos, ip->i_size);
+
+ xfs_rw_iunlock(ip, XFS_ILOCK_EXCL);
+ 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. xfs_ioend_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,
+ const struct iovec *iovp,
+ unsigned long nr_segs,
+ loff_t pos,
+ size_t ocount,
+ int *iolock)
+{
+ 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;
+ size_t count = ocount;
+ int unaligned_io = 0;
+ struct xfs_buftarg *target = XFS_IS_REALTIME_INODE(ip) ?
+ mp->m_rtdev_targp : mp->m_ddev_targp;
+
+ *iolock = 0;
+ if ((pos & target->bt_smask) || (count & target->bt_smask))
+ return -XFS_ERROR(EINVAL);
+
+ if ((pos & mp->m_blockmask) || ((pos + count) & mp->m_blockmask))
+ unaligned_io = 1;
+
+ if (unaligned_io || mapping->nrpages || pos > ip->i_size)
+ *iolock = XFS_IOLOCK_EXCL;
+ else
+ *iolock = XFS_IOLOCK_SHARED;
+ xfs_rw_ilock(ip, XFS_ILOCK_EXCL | *iolock);
+
+ ret = xfs_file_aio_write_checks(file, &pos, &count, iolock);
+ if (ret)
+ return ret;
+
+ if (mapping->nrpages) {
+ WARN_ON(*iolock != XFS_IOLOCK_EXCL);
+ ret = -xfs_flushinval_pages(ip, (pos & PAGE_CACHE_MASK), -1,
+ FI_REMAPF_LOCKED);
+ if (ret)
+ return ret;
+ }
+
+ /*
+ * 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)
+ xfs_ioend_wait(ip);
+ 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);
+ ret = generic_file_direct_write(iocb, iovp,
+ &nr_segs, pos, &iocb->ki_pos, count, ocount);
+
+ /* 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,
+ const struct iovec *iovp,
+ unsigned long nr_segs,
+ loff_t pos,
+ size_t ocount,
+ int *iolock)
+{
+ 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;
+ size_t count = ocount;
+
+ *iolock = XFS_IOLOCK_EXCL;
+ xfs_rw_ilock(ip, XFS_ILOCK_EXCL | *iolock);
+
+ ret = xfs_file_aio_write_checks(file, &pos, &count, iolock);
+ if (ret)
+ return ret;
+
+ /* We can write back this queue in page reclaim */
+ current->backing_dev_info = mapping->backing_dev_info;
+
+write_retry:
+ trace_xfs_file_buffered_write(ip, count, iocb->ki_pos, 0);
+ ret = generic_file_buffered_write(iocb, iovp, nr_segs,
+ pos, &iocb->ki_pos, count, ret);
+ /*
+ * if we just got an ENOSPC, flush the inode now we aren't holding any
+ * page locks and retry *once*
+ */
+ if (ret == -ENOSPC && !enospc) {
+ ret = -xfs_flush_pages(ip, 0, -1, 0, FI_NONE);
+ if (ret)
+ return ret;
+ enospc = 1;
+ goto write_retry;
+ }
+ current->backing_dev_info = NULL;
+ return ret;
+}
+
+STATIC ssize_t
+xfs_file_aio_write(
+ struct kiocb *iocb,
+ const struct iovec *iovp,
+ unsigned long nr_segs,
+ loff_t pos)
+{
+ 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 iolock;
+ size_t ocount = 0;
+
+ XFS_STATS_INC(xs_write_calls);
+
+ BUG_ON(iocb->ki_pos != pos);
+
+ ret = generic_segment_checks(iovp, &nr_segs, &ocount, VERIFY_READ);
+ if (ret)
+ return ret;
+
+ if (ocount == 0)
+ return 0;
+
+ xfs_wait_for_freeze(ip->i_mount, SB_FREEZE_WRITE);
+
+ if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+ return -EIO;
+
+ if (unlikely(file->f_flags & O_DIRECT))
+ ret = xfs_file_dio_aio_write(iocb, iovp, nr_segs, pos,
+ ocount, &iolock);
+ else
+ ret = xfs_file_buffered_aio_write(iocb, iovp, nr_segs, pos,
+ ocount, &iolock);
+
+ xfs_aio_write_isize_update(inode, &iocb->ki_pos, ret);
+
+ if (ret <= 0)
+ goto out_unlock;
+
+ /* Handle various SYNC-type writes */
+ if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
+ loff_t end = pos + ret - 1;
+ int error;
+
+ xfs_rw_iunlock(ip, iolock);
+ error = xfs_file_fsync(file, pos, end,
+ (file->f_flags & __O_SYNC) ? 0 : 1);
+ xfs_rw_ilock(ip, iolock);
+ if (error)
+ ret = error;
+ }
+
+out_unlock:
+ xfs_aio_write_newsize_update(ip);
+ xfs_rw_iunlock(ip, iolock);
+ return ret;
+}
+
+STATIC long
+xfs_file_fallocate(
+ struct file *file,
+ int mode,
+ loff_t offset,
+ loff_t len)
+{
+ struct inode *inode = file->f_path.dentry->d_inode;
+ long error;
+ loff_t new_size = 0;
+ xfs_flock64_t bf;
+ xfs_inode_t *ip = XFS_I(inode);
+ int cmd = XFS_IOC_RESVSP;
+ int attr_flags = XFS_ATTR_NOLOCK;
+
+ if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
+ return -EOPNOTSUPP;
+
+ bf.l_whence = 0;
+ bf.l_start = offset;
+ bf.l_len = len;
+
+ xfs_ilock(ip, XFS_IOLOCK_EXCL);
+
+ if (mode & FALLOC_FL_PUNCH_HOLE)
+ cmd = XFS_IOC_UNRESVSP;
+
+ /* check the new inode size is valid before allocating */
+ 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 (file->f_flags & O_DSYNC)
+ attr_flags |= XFS_ATTR_SYNC;
+
+ error = -xfs_change_file_space(ip, cmd, &bf, 0, attr_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, XFS_ATTR_NOLOCK);
+ }
+
+out_unlock:
+ xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+ 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_map_shared(ip);
+ if (ip->i_d.di_nextents > 0)
+ xfs_da_reada_buf(NULL, ip, 0, XFS_DATA_FORK);
+ 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 *filp,
+ void *dirent,
+ filldir_t filldir)
+{
+ struct inode *inode = filp->f_path.dentry->d_inode;
+ xfs_inode_t *ip = XFS_I(inode);
+ int error;
+ 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);
+
+ error = xfs_readdir(ip, dirent, bufsize,
+ (xfs_off_t *)&filp->f_pos, filldir);
+ if (error)
+ return -error;
+ return 0;
+}
+
+STATIC int
+xfs_file_mmap(
+ struct file *filp,
+ struct vm_area_struct *vma)
+{
+ vma->vm_ops = &xfs_file_vm_ops;
+ vma->vm_flags |= VM_CAN_NONLINEAR;
+
+ file_accessed(filp);
+ return 0;
+}
+
+/*
+ * 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_vm_page_mkwrite(
+ struct vm_area_struct *vma,
+ struct vm_fault *vmf)
+{
+ return block_page_mkwrite(vma, vmf, xfs_get_blocks);
+}
+
+const struct file_operations xfs_file_operations = {
+ .llseek = generic_file_llseek,
+ .read = do_sync_read,
+ .write = do_sync_write,
+ .aio_read = xfs_file_aio_read,
+ .aio_write = xfs_file_aio_write,
+ .splice_read = xfs_file_splice_read,
+ .splice_write = xfs_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,
+ .readdir = xfs_file_readdir,
+ .llseek = generic_file_llseek,
+ .unlocked_ioctl = xfs_file_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = xfs_file_compat_ioctl,
+#endif
+ .fsync = xfs_file_fsync,
+};
+
+static const struct vm_operations_struct xfs_file_vm_ops = {
+ .fault = filemap_fault,
+ .page_mkwrite = xfs_vm_page_mkwrite,
+};