On Fri, Aug 30, 2019 at 05:44:39AM +0100, Al Viro wrote:
> > Not quite right. XFS only returns an error if there is data
> > writeback failure or filesystem corruption or shutdown detected
> > during whatever operation it is performing.
> >
> > We don't really care what is done with the error that we return;
> > we're just returning an error because that's what the function
> > prototype indicates we should do...
>
> I thought that xfs_release() and friends followed the prototypes
> you had on IRIX, while xfs_file_release() et.al. were the
> impedance-matching layer for Linux. Oh, well...
That is how it started out originally. Since then a lot changed,
including the prototypes. We could easily do something like the
patch below. Additionally the read-only check probably should
check FMODE_WRITE instead, but that should be left for a separate
patch:
---
>From fbdf4e24ad1505129fb4db38644d11fa9b7e11f0 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <h...@lst.de>
Date: Sat, 31 Aug 2019 10:24:55 +0200
Subject: xfs: remove xfs_release
We can just move the code directly to xfs_file_release. Additionally
remove the pointless i_mode verification, and the error returns that
are entirely ignored by the calller of ->release.
Signed-off-by: Christoph Hellwig <h...@lst.de>
---
fs/xfs/xfs_file.c | 63 ++++++++++++++++++++++++++++++++++--
fs/xfs/xfs_inode.c | 80 ----------------------------------------------
fs/xfs/xfs_inode.h | 1 -
3 files changed, 60 insertions(+), 84 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index d952d5962e93..cbaba0cc1fa4 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1060,10 +1060,67 @@ xfs_dir_open(
STATIC int
xfs_file_release(
- struct inode *inode,
- struct file *filp)
+ struct inode *inode,
+ struct file *file)
{
- return xfs_release(XFS_I(inode));
+ struct xfs_inode *ip = XFS_I(inode);
+ struct xfs_mount *mp = ip->i_mount;
+
+ if ((mp->m_flags & XFS_MOUNT_RDONLY) || XFS_FORCED_SHUTDOWN(mp))
+ return 0;
+
+ /*
+ * If we previously truncated this file and removed old data in the
+ * process, we want to initiate "early" writeout on the last close.
+ * This is an attempt to combat the notorious NULL files problem which
+ * is particularly noticeable from a truncate down, buffered (re-)write
+ * (delalloc), followed by a crash. What we are effectively doing here
+ * is significantly reducing the time window where we'd otherwise be
+ * exposed to that problem.
+ */
+ if (xfs_iflags_test_and_clear(ip, XFS_ITRUNCATED)) {
+ xfs_iflags_clear(ip, XFS_IDIRTY_RELEASE);
+ if (ip->i_delayed_blks > 0)
+ filemap_flush(inode->i_mapping);
+ return 0;
+ }
+
+ if (inode->i_nlink == 0 || !xfs_can_free_eofblocks(ip, false))
+ return 0;
+
+ /*
+ * Check if the inode is being opened, written and closed frequently and
+ * we have delayed allocation blocks outstanding (e.g. streaming writes
+ * from the NFS server), truncating the blocks past EOF will cause
+ * fragmentation to occur.
+ *
+ * In this case don't do the truncation, but we have to be careful how
+ * we detect this case. Blocks beyond EOF show up as i_delayed_blks even
+ * when the inode is clean, so we need to truncate them away first
+ * before checking for a dirty release. Hence on the first dirty close
+ * we will still remove the speculative allocation, but after that we
+ * will leave it in place.
+ */
+ if (xfs_iflags_test(ip, XFS_IDIRTY_RELEASE))
+ return 0;
+
+ /*
+ * If we can't get the iolock just skip truncating the blocks past EOF
+ * because we could deadlock with the mmap_sem otherwise. We'll get
+ * another chance to drop them once the last reference to the inode is
+ * dropped, so we'll never leak blocks permanently.
+ */
+ if (xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
+ xfs_free_eofblocks(ip);
+ xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+ }
+
+ /*
+ * Delalloc blocks after truncation means it really is dirty.
+ */
+ if (ip->i_delayed_blks)
+ xfs_iflags_set(ip, XFS_IDIRTY_RELEASE);
+ return 0;
}
STATIC int
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index cdb97fa027fa..b0e85b7b8dc3 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1590,86 +1590,6 @@ xfs_itruncate_extents_flags(
return error;
}
-int
-xfs_release(
- xfs_inode_t *ip)
-{
- xfs_mount_t *mp = ip->i_mount;
- int error;
-
- if (!S_ISREG(VFS_I(ip)->i_mode) || (VFS_I(ip)->i_mode == 0))
- return 0;
-
- /* If this is a read-only mount, don't do this (would generate I/O) */
- if (mp->m_flags & XFS_MOUNT_RDONLY)
- return 0;
-
- if (!XFS_FORCED_SHUTDOWN(mp)) {
- int truncated;
-
- /*
- * If we previously truncated this file and removed old data
- * in the process, we want to initiate "early" writeout on
- * the last close. This is an attempt to combat the notorious
- * NULL files problem which is particularly noticeable from a
- * truncate down, buffered (re-)write (delalloc), followed by
- * a crash. What we are effectively doing here is
- * significantly reducing the time window where we'd otherwise
- * be exposed to that problem.
- */
- truncated = xfs_iflags_test_and_clear(ip, XFS_ITRUNCATED);
- if (truncated) {
- xfs_iflags_clear(ip, XFS_IDIRTY_RELEASE);
- if (ip->i_delayed_blks > 0) {
- error = filemap_flush(VFS_I(ip)->i_mapping);
- if (error)
- return error;
- }
- }
- }
-
- if (VFS_I(ip)->i_nlink == 0)
- return 0;
-
- if (xfs_can_free_eofblocks(ip, false)) {
-
- /*
- * Check if the inode is being opened, written and closed
- * frequently and we have delayed allocation blocks outstanding
- * (e.g. streaming writes from the NFS server), truncating the
- * blocks past EOF will cause fragmentation to occur.
- *
- * In this case don't do the truncation, but we have to be
- * careful how we detect this case. Blocks beyond EOF show up as
- * i_delayed_blks even when the inode is clean, so we need to
- * truncate them away first before checking for a dirty release.
- * Hence on the first dirty close we will still remove the
- * speculative allocation, but after that we will leave it in
- * place.
- */
- if (xfs_iflags_test(ip, XFS_IDIRTY_RELEASE))
- return 0;
- /*
- * If we can't get the iolock just skip truncating the blocks
- * past EOF because we could deadlock with the mmap_sem
- * otherwise. We'll get another chance to drop them once the
- * last reference to the inode is dropped, so we'll never leak
- * blocks permanently.
- */
- if (xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
- error = xfs_free_eofblocks(ip);
- xfs_iunlock(ip, XFS_IOLOCK_EXCL);
- if (error)
- return error;
- }
-
- /* delalloc blocks after truncation means it really is dirty */
- if (ip->i_delayed_blks)
- xfs_iflags_set(ip, XFS_IDIRTY_RELEASE);
- }
- return 0;
-}
-
/*
* xfs_inactive_truncate
*
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 558173f95a03..4299905135b2 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -410,7 +410,6 @@ enum layout_break_reason {
(((pip)->i_mount->m_flags & XFS_MOUNT_GRPID) || \
(VFS_I(pip)->i_mode & S_ISGID))
-int xfs_release(struct xfs_inode *ip);
void xfs_inactive(struct xfs_inode *ip);
int xfs_lookup(struct xfs_inode *dp, struct xfs_name *name,
struct xfs_inode **ipp, struct xfs_name *ci_name);
--
2.20.1
