The patch titled
Subject: shmem: recalculate file inode when fstat
has been added to the -mm tree. Its filename is
shmem-recalculate-file-inode-when-fstat.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/shmem-recalculate-file-inode-when-fstat.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/shmem-recalculate-file-inode-when-fstat.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Yu Zhao <yuzhao@xxxxxxxxxx>
Subject: shmem: recalculate file inode when fstat
Shmem uses shmem_recalc_inode to update i_blocks when it allocates page,
undoes range or swaps. But mm can drop clean page without notifying
shmem. This makes fstat sometimes return out-of-date block size.
The problem can be partially solved when we add inode_operations->getattr
which calls shmem_recalc_inode to update i_blocks for fstat.
shmem_recalc_inode also updates counter used by statfs and
vm_committed_as. For them the situation is not changed. They still
suffer from the discrepancy after dropping clean page and before the
function is called by aforementioned triggers.
Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff -puN mm/shmem.c~shmem-recalculate-file-inode-when-fstat mm/shmem.c
--- a/mm/shmem.c~shmem-recalculate-file-inode-when-fstat
+++ a/mm/shmem.c
@@ -542,6 +542,21 @@ void shmem_truncate_range(struct inode *
}
EXPORT_SYMBOL_GPL(shmem_truncate_range);
+static int shmem_getattr(struct vfsmount *mnt, struct dentry *dentry,
+ struct kstat *stat)
+{
+ struct inode *inode = dentry->d_inode;
+ struct shmem_inode_info *info = SHMEM_I(inode);
+
+ spin_lock(&info->lock);
+ shmem_recalc_inode(inode);
+ spin_unlock(&info->lock);
+
+ generic_fillattr(inode, stat);
+
+ return 0;
+}
+
static int shmem_setattr(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = d_inode(dentry);
@@ -3122,6 +3137,7 @@ static const struct file_operations shme
};
static const struct inode_operations shmem_inode_operations = {
+ .getattr = shmem_getattr,
.setattr = shmem_setattr,
#ifdef CONFIG_TMPFS_XATTR
.setxattr = shmem_setxattr,
_
Patches currently in -mm which might be from yuzhao@xxxxxxxxxx are
shmem-recalculate-file-inode-when-fstat.patch
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