On Mon 24-04-23 11:38:40, Baokun Li wrote: > If __es_remove_extent() returns an error it means that when splitting > extent, allocating an extent that must be kept failed, where returning > an error directly would cause the extent tree to be inconsistent. So we > use GFP_NOFAIL to pre-allocate an extent_status and pass it to > __es_remove_extent() to avoid this problem. > > In addition, since the allocated memory is outside the i_es_lock, the > extent_status tree may change and the pre-allocated extent_status is > no longer needed, so we release the pre-allocated extent_status when > es->es_len is not initialized. > > Suggested-by: Jan Kara <jack@xxxxxxx> > Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx> Looks good. Feel free to add: Reviewed-by: Jan Kara <jack@xxxxxxx> Honza > --- > fs/ext4/extents_status.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c > index 7219116e0d68..f4d50cd501fc 100644 > --- a/fs/ext4/extents_status.c > +++ b/fs/ext4/extents_status.c > @@ -1458,6 +1458,7 @@ int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk, > ext4_lblk_t end; > int err = 0; > int reserved = 0; > + struct extent_status *es = NULL; > > if (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY) > return 0; > @@ -1472,17 +1473,25 @@ int ext4_es_remove_extent(struct inode *inode, ext4_lblk_t lblk, > end = lblk + len - 1; > BUG_ON(end < lblk); > > +retry: > + if (err && !es) > + es = __es_alloc_extent(true); > /* > * ext4_clear_inode() depends on us taking i_es_lock unconditionally > * so that we are sure __es_shrink() is done with the inode before it > * is reclaimed. > */ > write_lock(&EXT4_I(inode)->i_es_lock); > - err = __es_remove_extent(inode, lblk, end, &reserved, NULL); > + err = __es_remove_extent(inode, lblk, end, &reserved, es); > + if (es && !es->es_len) > + __es_free_extent(es); > write_unlock(&EXT4_I(inode)->i_es_lock); > + if (err) > + goto retry; > + > ext4_es_print_tree(inode); > ext4_da_release_space(inode, reserved); > - return err; > + return 0; > } > > static int __es_shrink(struct ext4_sb_info *sbi, int nr_to_scan, > -- > 2.31.1 > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
