From 1cb51a15b576ee325d527726afff40947218fd5e Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Tue, 10 Jan 2017 11:49:40 +0100 Subject: [PATCH] ubifs: Fix journal replay wrt. xattr nodes When replaying the journal it can happen that a journal entry points to a garbage collected node. This is the case when a power-cut occurred between a garbage collect run and a commit. In such a case nodes have to be read using the failable read functions to detect whether the found node matches what we expect. One corner case was forgotten, when the journal contains an entry to remove an inode all xattrs have to be removed too. UBIFS models xattr like directory entries, so the TNC code iterates over all xattrs of the inode and removes them too. This code re-uses the functions for walking directories and calls ubifs_tnc_next_ent(). ubifs_tnc_next_ent() expects to be used only after the journal and aborts when a node does not match the expected result. This behavior can render an UBIFS volume unmountable after a power-cut when xattrs are used. Fix this issue by using failable read functions in ubifs_tnc_next_ent() too when replaying the journal. Cc: stable@vger.kernel.org Fixes: 1e51764a3c2ac05a ("UBIFS: add new flash file system") Reported-by: Rock Lee Reviewed-by: David Gstir Signed-off-by: Richard Weinberger --- fs/ubifs/tnc.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c index 74ae2de949df..709aa098dd46 100644 --- a/fs/ubifs/tnc.c +++ b/fs/ubifs/tnc.c @@ -34,6 +34,11 @@ #include #include "ubifs.h" +static int try_read_node(const struct ubifs_info *c, void *buf, int type, + int len, int lnum, int offs); +static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key, + struct ubifs_zbranch *zbr, void *node); + /* * Returned codes of 'matches_name()' and 'fallible_matches_name()' functions. * @NAME_LESS: name corresponding to the first argument is less than second @@ -402,7 +407,19 @@ static int tnc_read_hashed_node(struct ubifs_info *c, struct ubifs_zbranch *zbr, return 0; } - err = ubifs_tnc_read_node(c, zbr, node); + if (c->replaying) { + err = fallible_read_node(c, &zbr->key, zbr, node); + /* + * When the node was not found, return -ENOENT, 0 otherwise. + * Negative return codes stay as-is. + */ + if (err == 0) + err = -ENOENT; + else if (err == 1) + err = 0; + } else { + err = ubifs_tnc_read_node(c, zbr, node); + } if (err) return err; @@ -2857,7 +2874,11 @@ struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c, if (fname_len(nm) > 0) { if (err) { /* Handle collisions */ - err = resolve_collision(c, key, &znode, &n, nm); + if (c->replaying) + err = fallible_resolve_collision(c, key, &znode, &n, + nm, 0); + else + err = resolve_collision(c, key, &znode, &n, nm); dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n); if (unlikely(err < 0)) -- 2.20.1