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gfs2: Fix iomap buffer head reference counting bug

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GFS2 passes the inode buffer head (dibh) from gfs2_iomap_begin to
gfs2_iomap_end in iomap->private.  It sets that private pointer in
gfs2_iomap_get.  Users of gfs2_iomap_get other than gfs2_iomap_begin
would have to release iomap->private, but this isn't done correctly,
leading to a leak of buffer head references.

To fix this, move the code for setting iomap->private from
gfs2_iomap_get to gfs2_iomap_begin.

Fixes: 64bc06bb32 ("gfs2: iomap buffered write support")
Cc: stable@vger.kernel.org # v4.19+
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andreas Gruenbacher 2018-11-11 11:15:21 +00:00 committed by Linus Torvalds
parent e7445ceddf
commit c26b5aa8ef
1 changed files with 17 additions and 23 deletions
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40
fs/gfs2/bmap.c
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@ -826,7 +826,7 @@ static int gfs2_iomap_get(struct inode *inode, loff_t pos, loff_t length,
ret = gfs2_meta_inode_buffer(ip, &dibh); ret = gfs2_meta_inode_buffer(ip, &dibh);
if (ret) if (ret)
goto unlock; goto unlock;
iomap->private = dibh; mp->mp_bh[0] = dibh;
if (gfs2_is_stuffed(ip)) { if (gfs2_is_stuffed(ip)) {
if (flags & IOMAP_WRITE) { if (flags & IOMAP_WRITE) {
@ -863,9 +863,6 @@ unstuff:
len = lblock_stop - lblock + 1; len = lblock_stop - lblock + 1;
iomap->length = len << inode->i_blkbits; iomap->length = len << inode->i_blkbits;
get_bh(dibh);
mp->mp_bh[0] = dibh;
height = ip->i_height; height = ip->i_height;
while ((lblock + 1) * sdp->sd_sb.sb_bsize > sdp->sd_heightsize[height]) while ((lblock + 1) * sdp->sd_sb.sb_bsize > sdp->sd_heightsize[height])
height++; height++;
@ -898,8 +895,6 @@ out:
iomap->bdev = inode->i_sb->s_bdev; iomap->bdev = inode->i_sb->s_bdev;
unlock: unlock:
up_read(&ip->i_rw_mutex); up_read(&ip->i_rw_mutex);
if (ret && dibh)
brelse(dibh);
return ret; return ret;
do_alloc: do_alloc:
@ -980,9 +975,9 @@ static void gfs2_iomap_journaled_page_done(struct inode *inode, loff_t pos,
static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos, static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos,
loff_t length, unsigned flags, loff_t length, unsigned flags,
struct iomap *iomap) struct iomap *iomap,
struct metapath *mp)
{ {
struct metapath mp = { .mp_aheight = 1, };
struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode); struct gfs2_sbd *sdp = GFS2_SB(inode);
unsigned int data_blocks = 0, ind_blocks = 0, rblocks; unsigned int data_blocks = 0, ind_blocks = 0, rblocks;
@ -996,9 +991,9 @@ static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos,
unstuff = gfs2_is_stuffed(ip) && unstuff = gfs2_is_stuffed(ip) &&
pos + length > gfs2_max_stuffed_size(ip); pos + length > gfs2_max_stuffed_size(ip);
ret = gfs2_iomap_get(inode, pos, length, flags, iomap, &mp); ret = gfs2_iomap_get(inode, pos, length, flags, iomap, mp);
if (ret) if (ret)
goto out_release; goto out_unlock;
alloc_required = unstuff || iomap->type == IOMAP_HOLE; alloc_required = unstuff || iomap->type == IOMAP_HOLE;
@ -1013,7 +1008,7 @@ static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos,
ret = gfs2_quota_lock_check(ip, &ap); ret = gfs2_quota_lock_check(ip, &ap);
if (ret) if (ret)
goto out_release; goto out_unlock;
ret = gfs2_inplace_reserve(ip, &ap); ret = gfs2_inplace_reserve(ip, &ap);
if (ret) if (ret)
@ -1038,17 +1033,15 @@ static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos,
ret = gfs2_unstuff_dinode(ip, NULL); ret = gfs2_unstuff_dinode(ip, NULL);
if (ret) if (ret)
goto out_trans_end; goto out_trans_end;
release_metapath(&mp); release_metapath(mp);
brelse(iomap->private);
iomap->private = NULL;
ret = gfs2_iomap_get(inode, iomap->offset, iomap->length, ret = gfs2_iomap_get(inode, iomap->offset, iomap->length,
flags, iomap, &mp); flags, iomap, mp);
if (ret) if (ret)
goto out_trans_end; goto out_trans_end;
} }
if (iomap->type == IOMAP_HOLE) { if (iomap->type == IOMAP_HOLE) {
ret = gfs2_iomap_alloc(inode, iomap, flags, &mp); ret = gfs2_iomap_alloc(inode, iomap, flags, mp);
if (ret) { if (ret) {
gfs2_trans_end(sdp); gfs2_trans_end(sdp);
gfs2_inplace_release(ip); gfs2_inplace_release(ip);
@ -1056,7 +1049,6 @@ static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos,
goto out_qunlock; goto out_qunlock;
} }
} }
release_metapath(&mp);
if (gfs2_is_jdata(ip)) if (gfs2_is_jdata(ip))
iomap->page_done = gfs2_iomap_journaled_page_done; iomap->page_done = gfs2_iomap_journaled_page_done;
return 0; return 0;
@ -1069,10 +1061,7 @@ out_trans_fail:
out_qunlock: out_qunlock:
if (alloc_required) if (alloc_required)
gfs2_quota_unlock(ip); gfs2_quota_unlock(ip);
out_release: out_unlock:
if (iomap->private)
brelse(iomap->private);
release_metapath(&mp);
gfs2_write_unlock(inode); gfs2_write_unlock(inode);
return ret; return ret;
} }
@ -1088,10 +1077,10 @@ static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
trace_gfs2_iomap_start(ip, pos, length, flags); trace_gfs2_iomap_start(ip, pos, length, flags);
if ((flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT)) { if ((flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT)) {
ret = gfs2_iomap_begin_write(inode, pos, length, flags, iomap); ret = gfs2_iomap_begin_write(inode, pos, length, flags, iomap, &mp);
} else { } else {
ret = gfs2_iomap_get(inode, pos, length, flags, iomap, &mp); ret = gfs2_iomap_get(inode, pos, length, flags, iomap, &mp);
release_metapath(&mp);
/* /*
* Silently fall back to buffered I/O for stuffed files or if * Silently fall back to buffered I/O for stuffed files or if
* we've hot a hole (see gfs2_file_direct_write). * we've hot a hole (see gfs2_file_direct_write).
@ -1100,6 +1089,11 @@ static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
iomap->type != IOMAP_MAPPED) iomap->type != IOMAP_MAPPED)
ret = -ENOTBLK; ret = -ENOTBLK;
} }
if (!ret) {
get_bh(mp.mp_bh[0]);
iomap->private = mp.mp_bh[0];
}
release_metapath(&mp);
trace_gfs2_iomap_end(ip, iomap, ret); trace_gfs2_iomap_end(ip, iomap, ret);
return ret; return ret;
} }