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xfs: remove the i_new_size field in struct xfs_inode

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Now that we use the VFS i_size field throughout XFS there is no need for the
i_new_size field any more given that the VFS i_size field gets updated
in ->write_end before unlocking the page, and thus is always uptodate when
writeback could see a page.  Removing i_new_size also has the advantage that
we will never have to trim back di_size during a failed buffered write,
given that it never gets updated past i_size.

Note that currently the generic direct I/O code only updates i_size after
calling our end_io handler, which requires a small workaround to make
sure di_size actually makes it to disk.  I hope to fix this properly in
the generic code.

A downside is that we lose the support for parallel non-overlapping O_DIRECT
appending writes that recently was added.  I don't think keeping the complex
and fragile i_new_size infrastructure for this is a good tradeoff - if we
really care about parallel appending writers we should investigate turning
the iolock into a range lock, which would also allow for parallel
non-overlapping buffered writers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
This commit is contained in:
Christoph Hellwig
2011-12-18 20:00:12 +00:00
committed by Ben Myers
parent ce7ae151dd
commit 2813d682e8
5 changed files with 30 additions and 92 deletions
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18
fs/xfs/xfs_trace.h
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@ -891,7 +891,6 @@ DECLARE_EVENT_CLASS(xfs_file_class,
__field(dev_t, dev)
__field(xfs_ino_t, ino)
__field(xfs_fsize_t, size)
__field(xfs_fsize_t, new_size)
__field(loff_t, offset)
__field(size_t, count)
__field(int, flags)
@ -900,17 +899,15 @@ DECLARE_EVENT_CLASS(xfs_file_class,
__entry->dev = VFS_I(ip)->i_sb->s_dev;
__entry->ino = ip->i_ino;
__entry->size = ip->i_d.di_size;
__entry->new_size = ip->i_new_size;
__entry->offset = offset;
__entry->count = count;
__entry->flags = flags;
),
TP_printk("dev %d:%d ino 0x%llx size 0x%llx new_size 0x%llx "
TP_printk("dev %d:%d ino 0x%llx size 0x%llx "
"offset 0x%llx count 0x%zx ioflags %s",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->ino,
__entry->size,
__entry->new_size,
__entry->offset,
__entry->count,
__print_flags(__entry->flags, "|", XFS_IO_FLAGS))
@ -978,7 +975,6 @@ DECLARE_EVENT_CLASS(xfs_imap_class,
__field(dev_t, dev)
__field(xfs_ino_t, ino)
__field(loff_t, size)
__field(loff_t, new_size)
__field(loff_t, offset)
__field(size_t, count)
__field(int, type)
@ -990,7 +986,6 @@ DECLARE_EVENT_CLASS(xfs_imap_class,
__entry->dev = VFS_I(ip)->i_sb->s_dev;
__entry->ino = ip->i_ino;
__entry->size = ip->i_d.di_size;
__entry->new_size = ip->i_new_size;
__entry->offset = offset;
__entry->count = count;
__entry->type = type;
@ -998,13 +993,11 @@ DECLARE_EVENT_CLASS(xfs_imap_class,
__entry->startblock = irec ? irec->br_startblock : 0;
__entry->blockcount = irec ? irec->br_blockcount : 0;
),
TP_printk("dev %d:%d ino 0x%llx size 0x%llx new_size 0x%llx "
"offset 0x%llx count %zd type %s "
"startoff 0x%llx startblock %lld blockcount 0x%llx",
TP_printk("dev %d:%d ino 0x%llx size 0x%llx offset 0x%llx count %zd "
"type %s startoff 0x%llx startblock %lld blockcount 0x%llx",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->ino,
__entry->size,
__entry->new_size,
__entry->offset,
__entry->count,
__print_symbolic(__entry->type, XFS_IO_TYPES),
@ -1031,7 +1024,6 @@ DECLARE_EVENT_CLASS(xfs_simple_io_class,
__field(xfs_ino_t, ino)
__field(loff_t, isize)
__field(loff_t, disize)
__field(loff_t, new_size)
__field(loff_t, offset)
__field(size_t, count)
),
@ -1040,17 +1032,15 @@ DECLARE_EVENT_CLASS(xfs_simple_io_class,
__entry->ino = ip->i_ino;
__entry->isize = VFS_I(ip)->i_size;
__entry->disize = ip->i_d.di_size;
__entry->new_size = ip->i_new_size;
__entry->offset = offset;
__entry->count = count;
),
TP_printk("dev %d:%d ino 0x%llx isize 0x%llx disize 0x%llx new_size 0x%llx "
TP_printk("dev %d:%d ino 0x%llx isize 0x%llx disize 0x%llx "
"offset 0x%llx count %zd",
MAJOR(__entry->dev), MINOR(__entry->dev),
__entry->ino,
__entry->isize,
__entry->disize,
__entry->new_size,
__entry->offset,
__entry->count)
);