jffs2: Improve post-mount CRC scan efficiency
We need to finish doing the CRC checks before we can allow writes to happen, and we currently process the inodes in order. This means a call to jffs2_get_ino_cache() for each possible inode# up to c->highest_ino. There may be a lot of lookups which fail, if the inode# space is used sparsely. And the inode# space is *often* used sparsely, if a file system contains a lot of stuff that was put there in the original image, followed by lots of creation and deletion of new files. Instead of processing them numerically with a lookup each time, just walk the hash buckets instead. [fix locking typo reported by Dan Carpenter] Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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@ -134,38 +134,60 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
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if (mutex_lock_interruptible(&c->alloc_sem))
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return -EINTR;
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for (;;) {
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/* We can't start doing GC until we've finished checking
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the node CRCs etc. */
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int bucket, want_ino;
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spin_lock(&c->erase_completion_lock);
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if (!c->unchecked_size)
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break;
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/* We can't start doing GC yet. We haven't finished checking
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the node CRCs etc. Do it now. */
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/* checked_ino is protected by the alloc_sem */
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if (c->checked_ino > c->highest_ino && xattr) {
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pr_crit("Checked all inodes but still 0x%x bytes of unchecked space?\n",
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c->unchecked_size);
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jffs2_dbg_dump_block_lists_nolock(c);
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spin_unlock(&c->erase_completion_lock);
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mutex_unlock(&c->alloc_sem);
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return -ENOSPC;
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}
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spin_unlock(&c->erase_completion_lock);
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if (!xattr)
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xattr = jffs2_verify_xattr(c);
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spin_lock(&c->inocache_lock);
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/* Instead of doing the inodes in numeric order, doing a lookup
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* in the hash for each possible number, just walk the hash
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* buckets of *existing* inodes. This means that we process
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* them out-of-order, but it can be a lot faster if there's
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* a sparse inode# space. Which there often is. */
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want_ino = c->check_ino;
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for (bucket = c->check_ino % c->inocache_hashsize ; bucket < c->inocache_hashsize; bucket++) {
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for (ic = c->inocache_list[bucket]; ic; ic = ic->next) {
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if (ic->ino < want_ino)
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continue;
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ic = jffs2_get_ino_cache(c, c->checked_ino++);
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if (ic->state != INO_STATE_CHECKEDABSENT &&
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ic->state != INO_STATE_PRESENT)
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goto got_next; /* with inocache_lock held */
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if (!ic) {
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spin_unlock(&c->inocache_lock);
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continue;
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jffs2_dbg(1, "Skipping ino #%u already checked\n",
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ic->ino);
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}
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want_ino = 0;
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}
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/* Point c->check_ino past the end of the last bucket. */
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c->check_ino = ((c->highest_ino + c->inocache_hashsize + 1) &
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~c->inocache_hashsize) - 1;
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spin_unlock(&c->inocache_lock);
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pr_crit("Checked all inodes but still 0x%x bytes of unchecked space?\n",
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c->unchecked_size);
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jffs2_dbg_dump_block_lists_nolock(c);
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mutex_unlock(&c->alloc_sem);
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return -ENOSPC;
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got_next:
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/* For next time round the loop, we want c->checked_ino to indicate
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* the *next* one we want to check. And since we're walking the
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* buckets rather than doing it sequentially, it's: */
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c->check_ino = ic->ino + c->inocache_hashsize;
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if (!ic->pino_nlink) {
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jffs2_dbg(1, "Skipping check of ino #%d with nlink/pino zero\n",
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ic->ino);
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@ -176,8 +198,6 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
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switch(ic->state) {
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case INO_STATE_CHECKEDABSENT:
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case INO_STATE_PRESENT:
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jffs2_dbg(1, "Skipping ino #%u already checked\n",
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ic->ino);
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spin_unlock(&c->inocache_lock);
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continue;
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@ -196,7 +216,7 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
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ic->ino);
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/* We need to come back again for the _same_ inode. We've
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made no progress in this case, but that should be OK */
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c->checked_ino--;
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c->check_ino = ic->ino;
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mutex_unlock(&c->alloc_sem);
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sleep_on_spinunlock(&c->inocache_wq, &c->inocache_lock);
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@ -49,7 +49,7 @@ struct jffs2_sb_info {
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struct mtd_info *mtd;
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uint32_t highest_ino;
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uint32_t checked_ino;
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uint32_t check_ino; /* *NEXT* inode to be checked */
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unsigned int flags;
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@ -846,8 +846,8 @@ int jffs2_thread_should_wake(struct jffs2_sb_info *c)
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return 1;
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if (c->unchecked_size) {
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jffs2_dbg(1, "jffs2_thread_should_wake(): unchecked_size %d, checked_ino #%d\n",
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c->unchecked_size, c->checked_ino);
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jffs2_dbg(1, "jffs2_thread_should_wake(): unchecked_size %d, check_ino #%d\n",
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c->unchecked_size, c->check_ino);
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return 1;
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}
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