Track negative entries v3
Track negative dentries by recording the generation number of the parent
directory in d_fsdata. The generation number for the parent directory is
recorded in the inode_info, which increments every time the lock on the
directory is dropped.
If the generation number of the parent directory and the negative dentry
matches, there is no need to perform the revalidate, else a revalidate
is forced. This improves performance in situations where nodes look for
the same non-existent file multiple times.
Thanks Mark for explaining the DLM sequence.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.de>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
diff --git a/fs/ocfs2/dcache.c b/fs/ocfs2/dcache.c
index b4957c7..edaded4 100644
--- a/fs/ocfs2/dcache.c
+++ b/fs/ocfs2/dcache.c
@@ -40,6 +40,14 @@
#include "inode.h"
#include "super.h"
+void ocfs2_dentry_attach_gen(struct dentry *dentry)
+{
+ unsigned long gen =
+ OCFS2_I(dentry->d_parent->d_inode)->ip_dir_lock_gen;
+ BUG_ON(dentry->d_inode);
+ dentry->d_fsdata = (void *)gen;
+}
+
static int ocfs2_dentry_revalidate(struct dentry *dentry,
struct nameidata *nd)
@@ -51,11 +59,20 @@
mlog_entry("(0x%p, '%.*s')\n", dentry,
dentry->d_name.len, dentry->d_name.name);
- /* Never trust a negative dentry - force a new lookup. */
+ /* For a negative dentry -
+ * check the generation number of the parent and compare with the
+ * one stored in the inode.
+ */
if (inode == NULL) {
- mlog(0, "negative dentry: %.*s\n", dentry->d_name.len,
- dentry->d_name.name);
- goto bail;
+ unsigned long gen = (unsigned long) dentry->d_fsdata;
+ unsigned long pgen =
+ OCFS2_I(dentry->d_parent->d_inode)->ip_dir_lock_gen;
+ mlog(0, "negative dentry: %.*s parent gen: %lu "
+ "dentry gen: %lu\n",
+ dentry->d_name.len, dentry->d_name.name, pgen, gen);
+ if (gen != pgen)
+ goto bail;
+ goto valid;
}
BUG_ON(!osb);
@@ -96,6 +113,7 @@
goto bail;
}
+valid:
ret = 1;
bail:
@@ -227,6 +245,12 @@
if (!inode)
return 0;
+ if (!dentry->d_inode && dentry->d_fsdata) {
+ /* Converting a negative dentry to positive
+ Clear dentry->d_fsdata */
+ dentry->d_fsdata = dl = NULL;
+ }
+
if (dl) {
mlog_bug_on_msg(dl->dl_parent_blkno != parent_blkno,
" \"%.*s\": old parent: %llu, new: %llu\n",
@@ -452,6 +476,7 @@
out:
iput(inode);
+ ocfs2_dentry_attach_gen(dentry);
}
/*
diff --git a/fs/ocfs2/dcache.h b/fs/ocfs2/dcache.h
index f5dd178..b79eff7 100644
--- a/fs/ocfs2/dcache.h
+++ b/fs/ocfs2/dcache.h
@@ -64,5 +64,6 @@
struct inode *old_dir, struct inode *new_dir);
extern spinlock_t dentry_attach_lock;
+void ocfs2_dentry_attach_gen(struct dentry *dentry);
#endif /* OCFS2_DCACHE_H */
diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 5e02a89..e8d94d7 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -3635,10 +3635,18 @@
{
struct inode *inode;
struct address_space *mapping;
+ struct ocfs2_inode_info *oi;
inode = ocfs2_lock_res_inode(lockres);
mapping = inode->i_mapping;
+ if (S_ISDIR(inode->i_mode)) {
+ oi = OCFS2_I(inode);
+ oi->ip_dir_lock_gen++;
+ mlog(0, "generation: %u\n", oi->ip_dir_lock_gen);
+ goto out;
+ }
+
if (!S_ISREG(inode->i_mode))
goto out;
diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index eece3e0..f935fd6 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -335,6 +335,7 @@
else
inode->i_fop = &ocfs2_dops_no_plocks;
i_size_write(inode, le64_to_cpu(fe->i_size));
+ OCFS2_I(inode)->ip_dir_lock_gen = 1;
break;
case S_IFLNK:
if (ocfs2_inode_is_fast_symlink(inode))
diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h
index 0bc477a..1c508b1 100644
--- a/fs/ocfs2/inode.h
+++ b/fs/ocfs2/inode.h
@@ -67,6 +67,7 @@
/* Only valid if the inode is the dir. */
u32 ip_last_used_slot;
u64 ip_last_used_group;
+ u32 ip_dir_lock_gen;
struct ocfs2_alloc_reservation ip_la_data_resv;
};
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index a00dda2..e7bde21 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -171,7 +171,8 @@
ret = ERR_PTR(status);
goto bail_unlock;
}
- }
+ } else
+ ocfs2_dentry_attach_gen(dentry);
bail_unlock:
/* Don't drop the cluster lock until *after* the d_add --