From: Andreas Gruenbacher <agruenba@redhat.com> stable inclusion from stable-v5.10.252 commit d1a71694e0260c0a9beb623aaab15201fc65fb66 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15235 CVE: CVE-2026-45984 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit b924bdab7445946e2ed364a0e6e249d36f1f1158 ] So far, for buffered writes, we were taking the inode glock in gfs2_iomap_begin and dropping it in gfs2_iomap_end with the intention of not holding the inode glock while iomap_write_actor faults in user pages. It turns out that iomap_write_actor is called inside iomap_begin ... iomap_end, so the user pages were still faulted in while holding the inode glock and the locking code in iomap_begin / iomap_end was completely pointless. Move the locking into gfs2_file_buffered_write instead. We'll take care of the potential deadlocks due to faulting in user pages while holding a glock in a subsequent patch. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Stable-dep-of: faddeb848305 ("gfs2: Fix use-after-free in iomap inline data write path") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Hongbo Li <lihongbo22@huawei.com> --- fs/gfs2/bmap.c | 60 +------------------------------------------------- fs/gfs2/file.c | 27 +++++++++++++++++++++++ 2 files changed, 28 insertions(+), 59 deletions(-) diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c index 4514d9a8d3cd..f7d51dd6559c 100644 --- a/fs/gfs2/bmap.c +++ b/fs/gfs2/bmap.c @@ -958,46 +958,6 @@ static int __gfs2_iomap_get(struct inode *inode, loff_t pos, loff_t length, goto out; } -static int gfs2_write_lock(struct inode *inode) -{ - struct gfs2_inode *ip = GFS2_I(inode); - struct gfs2_sbd *sdp = GFS2_SB(inode); - int error; - - gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh); - error = gfs2_glock_nq(&ip->i_gh); - if (error) - goto out_uninit; - if (&ip->i_inode == sdp->sd_rindex) { - struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); - - error = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, - GL_NOCACHE, &m_ip->i_gh); - if (error) - goto out_unlock; - } - return 0; - -out_unlock: - gfs2_glock_dq(&ip->i_gh); -out_uninit: - gfs2_holder_uninit(&ip->i_gh); - return error; -} - -static void gfs2_write_unlock(struct inode *inode) -{ - struct gfs2_inode *ip = GFS2_I(inode); - struct gfs2_sbd *sdp = GFS2_SB(inode); - - if (&ip->i_inode == sdp->sd_rindex) { - struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); - - gfs2_glock_dq_uninit(&m_ip->i_gh); - } - gfs2_glock_dq_uninit(&ip->i_gh); -} - static int gfs2_iomap_page_prepare(struct inode *inode, loff_t pos, unsigned len, struct iomap *iomap) { @@ -1116,11 +1076,6 @@ static int gfs2_iomap_begin_write(struct inode *inode, loff_t pos, return ret; } -static inline bool gfs2_iomap_need_write_lock(unsigned flags) -{ - return (flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT); -} - static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length, unsigned flags, struct iomap *iomap, struct iomap *srcmap) @@ -1133,12 +1088,6 @@ static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length, iomap->flags |= IOMAP_F_BUFFER_HEAD; trace_gfs2_iomap_start(ip, pos, length, flags); - if (gfs2_iomap_need_write_lock(flags)) { - ret = gfs2_write_lock(inode); - if (ret) - goto out; - } - ret = __gfs2_iomap_get(inode, pos, length, flags, iomap, &mp); if (ret) goto out_unlock; @@ -1166,10 +1115,7 @@ static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length, ret = gfs2_iomap_begin_write(inode, pos, length, flags, iomap, &mp); out_unlock: - if (ret && gfs2_iomap_need_write_lock(flags)) - gfs2_write_unlock(inode); release_metapath(&mp); -out: trace_gfs2_iomap_end(ip, iomap, ret); return ret; } @@ -1216,15 +1162,11 @@ static int gfs2_iomap_end(struct inode *inode, loff_t pos, loff_t length, } if (unlikely(!written)) - goto out_unlock; + return 0; if (iomap->flags & IOMAP_F_SIZE_CHANGED) mark_inode_dirty(inode); set_bit(GLF_DIRTY, &ip->i_gl->gl_flags); - -out_unlock: - if (gfs2_iomap_need_write_lock(flags)) - gfs2_write_unlock(inode); return 0; } diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index 52c16848a2fd..06dc4fee7be1 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -888,13 +888,40 @@ static ssize_t gfs2_file_buffered_write(struct kiocb *iocb, struct iov_iter *fro { struct file *file = iocb->ki_filp; struct inode *inode = file_inode(file); + struct gfs2_inode *ip = GFS2_I(inode); + struct gfs2_sbd *sdp = GFS2_SB(inode); ssize_t ret; + gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh); + ret = gfs2_glock_nq(&ip->i_gh); + if (ret) + goto out_uninit; + + if (inode == sdp->sd_rindex) { + struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); + + ret = gfs2_glock_nq_init(m_ip->i_gl, LM_ST_EXCLUSIVE, + GL_NOCACHE, &m_ip->i_gh); + if (ret) + goto out_unlock; + } + current->backing_dev_info = inode_to_bdi(inode); ret = iomap_file_buffered_write(iocb, from, &gfs2_iomap_ops); current->backing_dev_info = NULL; if (ret > 0) iocb->ki_pos += ret; + + if (inode == sdp->sd_rindex) { + struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); + + gfs2_glock_dq_uninit(&m_ip->i_gh); + } + +out_unlock: + gfs2_glock_dq(&ip->i_gh); +out_uninit: + gfs2_holder_uninit(&ip->i_gh); return ret; } -- 2.34.1