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Linux: Fix ZFS_ENTER/ZFS_EXIT/ZFS_VERFY_ZP usage 

The ZFS_ENTER/ZFS_EXIT/ZFS_VERFY_ZP macros should not be used
in the Linux zpl_*.c source files.  They return a positive error
value which is correct for the common code, but not for the Linux
specific kernel code which expects a negative return value.  The
ZPL_ENTER/ZPL_EXIT/ZPL_VERFY_ZP macros should be used instead.

Furthermore, the ZPL_EXIT macro has been updated to not call the
zfs_exit_fs() function.  This prevents a possible deadlock which
can occur when a snapshot is automatically unmounted because the
zpl_show_devname() must never wait on in progress automatic
snapshot unmounts.

Reviewed-by: Adam Moss <c@yotes.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #11169 
Closes #11201
This commit is contained in:
Brian Behlendorf 2020-11-14 10:19:00 -08:00 committed by GitHub
parent d66aab7c08
commit 4352edaafb
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 23 additions and 19 deletions
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6
include/os/linux/zfs/sys/zfs_znode_impl.h
View File

@ -94,7 +94,11 @@ do { \
zfs_exit_fs(zfsvfs); \
rrm_exit(&(zfsvfs)->z_teardown_lock, FTAG); \
} while (0)
#define ZPL_EXIT(zfsvfs) ZFS_EXIT(zfsvfs)
#define ZPL_EXIT(zfsvfs) \
do { \
rrm_exit(&(zfsvfs)->z_teardown_lock, FTAG); \
} while (0)
/* Verifies the znode is valid. */
#define ZFS_VERIFY_ZP_ERROR(zp, error) \

22
module/os/linux/zfs/zpl_ctldir.c
View File

@ -55,7 +55,7 @@ zpl_root_iterate(struct file *filp, zpl_dir_context_t *ctx)
zfsvfs_t *zfsvfs = ITOZSB(file_inode(filp));
int error = 0;
ZFS_ENTER(zfsvfs);
ZPL_ENTER(zfsvfs);
if (!zpl_dir_emit_dots(filp, ctx))
goto out;
@ -76,7 +76,7 @@ zpl_root_iterate(struct file *filp, zpl_dir_context_t *ctx)
ctx->pos++;
}
out:
ZFS_EXIT(zfsvfs);
ZPL_EXIT(zfsvfs);
return (error);
}
@ -242,7 +242,7 @@ zpl_snapdir_iterate(struct file *filp, zpl_dir_context_t *ctx)
uint64_t id, pos;
int error = 0;
ZFS_ENTER(zfsvfs);
ZPL_ENTER(zfsvfs);
cookie = spl_fstrans_mark();
if (!zpl_dir_emit_dots(filp, ctx))
@ -266,7 +266,7 @@ zpl_snapdir_iterate(struct file *filp, zpl_dir_context_t *ctx)
}
out:
spl_fstrans_unmark(cookie);
ZFS_EXIT(zfsvfs);
ZPL_EXIT(zfsvfs);
if (error == -ENOENT)
return (0);
@ -369,13 +369,13 @@ zpl_snapdir_getattr_impl(const struct path *path, struct kstat *stat,
struct inode *ip = path->dentry->d_inode;
zfsvfs_t *zfsvfs = ITOZSB(ip);
ZFS_ENTER(zfsvfs);
ZPL_ENTER(zfsvfs);
generic_fillattr(ip, stat);
stat->nlink = stat->size = 2;
stat->ctime = stat->mtime = dmu_objset_snap_cmtime(zfsvfs->z_os);
stat->atime = current_time(ip);
ZFS_EXIT(zfsvfs);
ZPL_EXIT(zfsvfs);
return (0);
}
@ -453,7 +453,7 @@ zpl_shares_iterate(struct file *filp, zpl_dir_context_t *ctx)
znode_t *dzp;
int error = 0;
ZFS_ENTER(zfsvfs);
ZPL_ENTER(zfsvfs);
cookie = spl_fstrans_mark();
if (zfsvfs->z_shares_dir == 0) {
@ -472,7 +472,7 @@ zpl_shares_iterate(struct file *filp, zpl_dir_context_t *ctx)
iput(ZTOI(dzp));
out:
spl_fstrans_unmark(cookie);
ZFS_EXIT(zfsvfs);
ZPL_EXIT(zfsvfs);
ASSERT3S(error, <=, 0);
return (error);
@ -503,13 +503,13 @@ zpl_shares_getattr_impl(const struct path *path, struct kstat *stat,
znode_t *dzp;
int error;
ZFS_ENTER(zfsvfs);
ZPL_ENTER(zfsvfs);
if (zfsvfs->z_shares_dir == 0) {
generic_fillattr(path->dentry->d_inode, stat);
stat->nlink = stat->size = 2;
stat->atime = current_time(ip);
ZFS_EXIT(zfsvfs);
ZPL_EXIT(zfsvfs);
return (0);
}
@ -519,7 +519,7 @@ zpl_shares_getattr_impl(const struct path *path, struct kstat *stat,
iput(ZTOI(dzp));
}
ZFS_EXIT(zfsvfs);
ZPL_EXIT(zfsvfs);
ASSERT3S(error, <=, 0);
return (error);

10
module/os/linux/zfs/zpl_file.c
View File

@ -673,10 +673,10 @@ zpl_writepages(struct address_space *mapping, struct writeback_control *wbc)
enum writeback_sync_modes sync_mode;
int result;
ZFS_ENTER(zfsvfs);
ZPL_ENTER(zfsvfs);
if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
wbc->sync_mode = WB_SYNC_ALL;
ZFS_EXIT(zfsvfs);
ZPL_EXIT(zfsvfs);
sync_mode = wbc->sync_mode;
/*
@ -689,11 +689,11 @@ zpl_writepages(struct address_space *mapping, struct writeback_control *wbc)
wbc->sync_mode = WB_SYNC_NONE;
result = write_cache_pages(mapping, wbc, zpl_putpage, mapping);
if (sync_mode != wbc->sync_mode) {
ZFS_ENTER(zfsvfs);
ZFS_VERIFY_ZP(zp);
ZPL_ENTER(zfsvfs);
ZPL_VERIFY_ZP(zp);
if (zfsvfs->z_log != NULL)
zil_commit(zfsvfs->z_log, zp->z_id);
ZFS_EXIT(zfsvfs);
ZPL_EXIT(zfsvfs);
/*
* We need to call write_cache_pages() again (we can't just

4
module/os/linux/zfs/zpl_super.c
View File

@ -185,7 +185,7 @@ zpl_remount_fs(struct super_block *sb, int *flags, char *data)
static int
__zpl_show_devname(struct seq_file *seq, zfsvfs_t *zfsvfs)
{
ZFS_ENTER(zfsvfs);
ZPL_ENTER(zfsvfs);
char *fsname = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
dmu_objset_name(zfsvfs->z_os, fsname);
@ -205,7 +205,7 @@ __zpl_show_devname(struct seq_file *seq, zfsvfs_t *zfsvfs)
kmem_free(fsname, ZFS_MAX_DATASET_NAME_LEN);
ZFS_EXIT(zfsvfs);
ZPL_EXIT(zfsvfs);
return (0);
}