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authorAdrian Hunter <ext-adrian.hunter@nokia.com>2008-08-22 07:23:35 -0400
committerArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2008-08-25 07:34:02 -0400
commit601c0bc46753007be011b513ba4fc50ed8e30aef (patch)
tree39017065a8418b60362686a7771afe138e100c08 /fs/ubifs/gc.c
parent761e29f3bb19b05bea55285dfdf2d28e001a63b8 (diff)
UBIFS: allow for racing between GC and TNC
The TNC mutex is unlocked prematurely when reading leaf nodes with non-hashed keys. This is unsafe because the node may be moved by garbage collection and the eraseblock unmapped, although that has never actually happened during stress testing. This patch fixes the flaw by detecting the race and retrying with the TNC mutex locked. Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Diffstat (limited to 'fs/ubifs/gc.c')
-rw-r--r--fs/ubifs/gc.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c
index d0f3dac29081..13f1019c859f 100644
--- a/fs/ubifs/gc.c
+++ b/fs/ubifs/gc.c
@@ -344,6 +344,12 @@ int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp)
344 if (err) 344 if (err)
345 goto out; 345 goto out;
346 346
347 /* Allow for races with TNC */
348 c->gced_lnum = lnum;
349 smp_wmb();
350 c->gc_seq += 1;
351 smp_wmb();
352
347 if (c->gc_lnum == -1) { 353 if (c->gc_lnum == -1) {
348 c->gc_lnum = lnum; 354 c->gc_lnum = lnum;
349 err = LEB_RETAINED; 355 err = LEB_RETAINED;