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Subject[PATCH 14/32] Unionfs: file_revalidate updates
Date
From: Erez Zadok <ezk@cs.sunysb.edu>

Correctly revalidate a file and account for lower mnts, even when branches
are updated or inserted. Better info upon file copyup.

Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
---
fs/unionfs/commonfops.c | 25 +++++++++++++++++++++----
1 files changed, 21 insertions(+), 4 deletions(-)
diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c
index 64bd0bd..612207a 100644
--- a/fs/unionfs/commonfops.c
+++ b/fs/unionfs/commonfops.c
@@ -333,6 +333,9 @@ int unionfs_file_revalidate(struct file *file, int willwrite)
*/
if (!d_deleted(dentry) &&
(sbgen > fgen || dbstart(dentry) != fbstart(file))) {
+ /* save orig branch ID */
+ int orig_brid = UNIONFS_F(file)->saved_branch_ids[fbstart(file)];
+
/* First we throw out the existing files. */
cleanup_file(file);

@@ -359,22 +362,36 @@ int unionfs_file_revalidate(struct file *file, int willwrite)
if (err)
goto out;
} else {
+ int new_brid;
/* We only open the highest priority branch. */
err = open_highest_file(file, willwrite);
if (err)
goto out;
+ new_brid = UNIONFS_F(file)->
+ saved_branch_ids[fbstart(file)];
+ if (new_brid != orig_brid && sbgen > fgen) {
+ /*
+ * If we re-opened the file on a different
+ * branch than the original one, and this
+ * was due to a new branch inserted, then
+ * update the mnt counts of the old and new
+ * branches accordingly.
+ */
+ unionfs_mntget(dentry, bstart);
+ unionfs_mntput(sb->s_root,
+ branch_id_to_idx(sb, orig_brid));
+ }
}
atomic_set(&UNIONFS_F(file)->generation,
- atomic_read(&UNIONFS_I(dentry->d_inode)->
- generation));
+ atomic_read(&UNIONFS_I(dentry->d_inode)->generation));
}

/* Copyup on the first write to a file on a readonly branch. */
if (willwrite && IS_WRITE_FLAG(file->f_flags) &&
!IS_WRITE_FLAG(unionfs_lower_file(file)->f_flags) &&
is_robranch(dentry)) {
- printk(KERN_DEBUG "unionfs: Doing delayed copyup of a "
- "read-write file on a read-only branch.\n");
+ printk(KERN_DEBUG "unionfs: do delay copyup of \"%s\"\n",
+ dentry->d_name.name);
err = do_delayed_copyup(file);
}

--
1.5.2.2.238.g7cbf2f2
-
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