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| author | Al Viro <viro@zeniv.linux.org.uk> | 2014-05-01 10:30:00 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2014-05-01 10:30:00 -0400 |
| commit | 41edf278fc2f042f4e22a12ed87d19c5201210e1 (patch) | |
| tree | 4f49bfe5f401dcc7477fb630f3773a59402b634a | |
| parent | 01b6035190b024240a43ac1d8e9c6f964f5f1c63 (diff) | |
| download | lwn-41edf278fc2f042f4e22a12ed87d19c5201210e1.tar.gz lwn-41edf278fc2f042f4e22a12ed87d19c5201210e1.zip | |
dentry_kill(): don't try to remove from shrink list
If the victim in on the shrink list, don't remove it from there.
If shrink_dentry_list() manages to remove it from the list before
we are done - fine, we'll just free it as usual. If not - mark
it with new flag (DCACHE_MAY_FREE) and leave it there.
Eventually, shrink_dentry_list() will get to it, remove the sucker
from shrink list and call dentry_kill(dentry, 0). Which is where
we'll deal with freeing.
Since now dentry_kill(dentry, 0) may happen after or during
dentry_kill(dentry, 1), we need to recognize that (by seeing
DCACHE_DENTRY_KILLED already set), unlock everything
and either free the sucker (in case DCACHE_MAY_FREE has been
set) or leave it for ongoing dentry_kill(dentry, 1) to deal with.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/dcache.c | 27 | ||||
| -rw-r--r-- | include/linux/dcache.h | 2 |
2 files changed, 21 insertions, 8 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index e482775343a0..58e26bee7ef4 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -468,7 +468,14 @@ dentry_kill(struct dentry *dentry, int unlock_on_failure) __releases(dentry->d_lock) { struct inode *inode; - struct dentry *parent; + struct dentry *parent = NULL; + bool can_free = true; + + if (unlikely(dentry->d_flags & DCACHE_DENTRY_KILLED)) { + can_free = dentry->d_flags & DCACHE_MAY_FREE; + spin_unlock(&dentry->d_lock); + goto out; + } inode = dentry->d_inode; if (inode && !spin_trylock(&inode->i_lock)) { @@ -479,9 +486,7 @@ relock: } return dentry; /* try again with same dentry */ } - if (IS_ROOT(dentry)) - parent = NULL; - else + if (!IS_ROOT(dentry)) parent = dentry->d_parent; if (parent && !spin_trylock(&parent->d_lock)) { if (inode) @@ -504,8 +509,6 @@ relock: if (dentry->d_flags & DCACHE_LRU_LIST) { if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) d_lru_del(dentry); - else - d_shrink_del(dentry); } /* if it was on the hash then remove it */ __d_drop(dentry); @@ -527,7 +530,15 @@ relock: if (dentry->d_op && dentry->d_op->d_release) dentry->d_op->d_release(dentry); - dentry_free(dentry); + spin_lock(&dentry->d_lock); + if (dentry->d_flags & DCACHE_SHRINK_LIST) { + dentry->d_flags |= DCACHE_MAY_FREE; + can_free = false; + } + spin_unlock(&dentry->d_lock); +out: + if (likely(can_free)) + dentry_free(dentry); return parent; } @@ -829,7 +840,7 @@ static void shrink_dentry_list(struct list_head *list) * We found an inuse dentry which was not removed from * the LRU because of laziness during lookup. Do not free it. */ - if (dentry->d_lockref.count) { + if ((int)dentry->d_lockref.count > 0) { spin_unlock(&dentry->d_lock); continue; } diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 3b9bfdb83ba6..3c7ec327ebd2 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -221,6 +221,8 @@ struct dentry_operations { #define DCACHE_SYMLINK_TYPE 0x00300000 /* Symlink */ #define DCACHE_FILE_TYPE 0x00400000 /* Other file type */ +#define DCACHE_MAY_FREE 0x00800000 + extern seqlock_t rename_lock; static inline int dname_external(const struct dentry *dentry) |