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Date: Sat, 16 Feb 2008 21:57:19 -0500
From: Erez Zadok <ezk@...sunysb.edu>
To: akpm@...ux-foundation.org
Cc: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
viro@....linux.org.uk, hch@...radead.org,
Erez Zadok <ezk@...sunysb.edu>
Subject: [PATCH 10/17] Unionfs: factor out revalidation routine
To be used by rest of revalidation code, as well a callers who already
locked the child and parent dentry branch-configurations.
Signed-off-by: Erez Zadok <ezk@...sunysb.edu>
---
fs/unionfs/dentry.c | 87 +++++++++++++++++++++++++++++++-------------------
fs/unionfs/union.h | 3 ++
2 files changed, 57 insertions(+), 33 deletions(-)
diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c
index afa2120..3bd2dfb 100644
--- a/fs/unionfs/dentry.c
+++ b/fs/unionfs/dentry.c
@@ -285,6 +285,59 @@ void purge_sb_data(struct super_block *sb)
}
/*
+ * Revalidate a single file/symlink/special dentry. Assume that info nodes
+ * of the dentry and its parent are locked. Assume that parent(s) are all
+ * valid already, but the child may not yet be valid. Returns true if
+ * valid, false otherwise.
+ */
+bool __unionfs_d_revalidate_one_locked(struct dentry *dentry,
+ struct nameidata *nd,
+ bool willwrite)
+{
+ bool valid = false; /* default is invalid */
+ int sbgen, dgen, bindex;
+
+ verify_locked(dentry);
+ verify_locked(dentry->d_parent);
+
+ sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation);
+ dgen = atomic_read(&UNIONFS_D(dentry)->generation);
+
+ if (unlikely(is_newer_lower(dentry))) {
+ /* root dentry special case as aforementioned */
+ if (IS_ROOT(dentry)) {
+ unionfs_copy_attr_times(dentry->d_inode);
+ } else {
+ /*
+ * reset generation number to zero, guaranteed to be
+ * "old"
+ */
+ dgen = 0;
+ atomic_set(&UNIONFS_D(dentry)->generation, dgen);
+ }
+ if (!willwrite)
+ purge_inode_data(dentry->d_inode);
+ }
+ valid = __unionfs_d_revalidate_one(dentry, nd);
+
+ /*
+ * If __unionfs_d_revalidate_one() succeeded above, then it will
+ * have incremented the refcnt of the mnt's, but also the branch
+ * indices of the dentry will have been updated (to take into
+ * account any branch insertions/deletion. So the current
+ * dbstart/dbend match the current, and new, indices of the mnts
+ * which __unionfs_d_revalidate_one has incremented. Note: the "if"
+ * test below does not depend on whether chain_len was 0 or greater.
+ */
+ if (!valid || sbgen == dgen)
+ goto out;
+ for (bindex = dbstart(dentry); bindex <= dbend(dentry); bindex++)
+ unionfs_mntput(dentry, bindex);
+out:
+ return valid;
+}
+
+/*
* Revalidate a parent chain of dentries, then the actual node.
* Assumes that dentry is locked, but will lock all parents if/when needed.
*
@@ -404,42 +457,10 @@ out_this:
if (dentry != dentry->d_parent)
unionfs_lock_dentry(dentry->d_parent,
UNIONFS_DMUTEX_REVAL_PARENT);
- dgen = atomic_read(&UNIONFS_D(dentry)->generation);
-
- if (unlikely(is_newer_lower(dentry))) {
- /* root dentry special case as aforementioned */
- if (IS_ROOT(dentry)) {
- unionfs_copy_attr_times(dentry->d_inode);
- } else {
- /*
- * reset generation number to zero, guaranteed to be
- * "old"
- */
- dgen = 0;
- atomic_set(&UNIONFS_D(dentry)->generation, dgen);
- }
- if (!willwrite)
- purge_inode_data(dentry->d_inode);
- }
- valid = __unionfs_d_revalidate_one(dentry, nd);
+ valid = __unionfs_d_revalidate_one_locked(dentry, nd, willwrite);
if (dentry != dentry->d_parent)
unionfs_unlock_dentry(dentry->d_parent);
- /*
- * If __unionfs_d_revalidate_one() succeeded above, then it will
- * have incremented the refcnt of the mnt's, but also the branch
- * indices of the dentry will have been updated (to take into
- * account any branch insertions/deletion. So the current
- * dbstart/dbend match the current, and new, indices of the mnts
- * which __unionfs_d_revalidate_one has incremented. Note: the "if"
- * test below does not depend on whether chain_len was 0 or greater.
- */
- if (valid && sbgen != dgen)
- for (bindex = dbstart(dentry);
- bindex <= dbend(dentry);
- bindex++)
- unionfs_mntput(dentry, bindex);
-
out_free:
/* unlock/dput all dentries in chain and return status */
if (chain_len > 0) {
diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h
index 0e0ccde..5001b07 100644
--- a/fs/unionfs/union.h
+++ b/fs/unionfs/union.h
@@ -368,6 +368,9 @@ extern int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
extern int unionfs_unlink(struct inode *dir, struct dentry *dentry);
extern int unionfs_rmdir(struct inode *dir, struct dentry *dentry);
+extern bool __unionfs_d_revalidate_one_locked(struct dentry *dentry,
+ struct nameidata *nd,
+ bool willwrite);
extern bool __unionfs_d_revalidate_chain(struct dentry *dentry,
struct nameidata *nd, bool willwrite);
extern bool is_newer_lower(const struct dentry *dentry);
--
1.5.2.2
--
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