[PATCH 20/28] ext4: improve journal credit handling in set xattr paths

From: Tahsin Erdogan
Date: Wed May 31 2017 - 04:25:31 EST


Both ext4_set_acl() and ext4_set_context() need to be made aware of
ea_inode feature when it comes to credits calculation.

Also add a sufficient credits check in ext4_xattr_set_handle() right
after xattr write lock is grabbed. Original credits calculation is done
outside the lock so there is a possiblity that the initially calculated
credits are not sufficient anymore.

Signed-off-by: Tahsin Erdogan <tahsin@xxxxxxxxxx>
---
fs/ext4/acl.c | 7 ++++---
fs/ext4/ext4_jbd2.h | 14 --------------
fs/ext4/super.c | 6 +++---
fs/ext4/xattr.c | 55 +++++++++++++++++++++++++++++++++++++++++------------
fs/ext4/xattr.h | 1 +
5 files changed, 51 insertions(+), 32 deletions(-)

diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
index 3ec0e46de95f..74f7ac539e00 100644
--- a/fs/ext4/acl.c
+++ b/fs/ext4/acl.c
@@ -231,14 +231,15 @@ int
ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
handle_t *handle;
- int error, retries = 0;
+ int error, credits, retries = 0;
+ size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0;

error = dquot_initialize(inode);
if (error)
return error;
retry:
- handle = ext4_journal_start(inode, EXT4_HT_XATTR,
- ext4_jbd2_credits_xattr(inode));
+ credits = ext4_xattr_set_credits(inode, acl_size);
+ handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
if (IS_ERR(handle))
return PTR_ERR(handle);

diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index f97611171023..a5bda70feed5 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -104,20 +104,6 @@
#define EXT4_MAXQUOTAS_INIT_BLOCKS(sb) (EXT4_MAXQUOTAS*EXT4_QUOTA_INIT_BLOCKS(sb))
#define EXT4_MAXQUOTAS_DEL_BLOCKS(sb) (EXT4_MAXQUOTAS*EXT4_QUOTA_DEL_BLOCKS(sb))

-static inline int ext4_jbd2_credits_xattr(struct inode *inode)
-{
- int credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb);
-
- /*
- * In case of inline data, we may push out the data to a block,
- * so we need to reserve credits for this eventuality
- */
- if (ext4_has_inline_data(inode))
- credits += ext4_writepage_trans_blocks(inode) + 1;
- return credits;
-}
-
-
/*
* Ext4 handle operation types -- for logging purposes
*/
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index d37c81f327e7..b02a23ec92ca 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1143,7 +1143,7 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
void *fs_data)
{
handle_t *handle = fs_data;
- int res, res2, retries = 0;
+ int res, res2, credits, retries = 0;

res = ext4_convert_inline_data(inode);
if (res)
@@ -1178,8 +1178,8 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
if (res)
return res;
retry:
- handle = ext4_journal_start(inode, EXT4_HT_MISC,
- ext4_jbd2_credits_xattr(inode));
+ credits = ext4_xattr_set_credits(inode, len);
+ handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
if (IS_ERR(handle))
return PTR_ERR(handle);

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 230e0aa76777..5bce73b43b2a 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1473,6 +1473,17 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,

ext4_write_lock_xattr(inode, &no_expand);

+ /* Check journal credits under write lock. */
+ if (ext4_handle_valid(handle)) {
+ int credits;
+
+ credits = ext4_xattr_set_credits(inode, value_len);
+ if (!ext4_handle_has_enough_credits(handle, credits)) {
+ error = -ENOSPC;
+ goto cleanup;
+ }
+ }
+
error = ext4_reserve_inode_write(handle, inode, &is.iloc);
if (error)
goto cleanup;
@@ -1570,6 +1581,36 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
return error;
}

+int ext4_xattr_set_credits(struct inode *inode, size_t value_len)
+{
+ struct super_block *sb = inode->i_sb;
+ int credits;
+
+ if (!EXT4_SB(sb)->s_journal)
+ return 0;
+
+ credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb);
+
+ /*
+ * In case of inline data, we may push out the data to a block,
+ * so we need to reserve credits for this eventuality
+ */
+ if (ext4_has_inline_data(inode))
+ credits += ext4_writepage_trans_blocks(inode) + 1;
+
+ if (ext4_has_feature_ea_inode(sb)) {
+ int nrblocks = (value_len + sb->s_blocksize - 1) >>
+ sb->s_blocksize_bits;
+
+ /* For new inode */
+ credits += EXT4_SINGLEDATA_TRANS_BLOCKS(sb) + 3;
+
+ /* For data blocks of EA inode */
+ credits += ext4_meta_trans_blocks(inode, nrblocks, 0);
+ }
+ return credits;
+}
+
/*
* ext4_xattr_set()
*
@@ -1585,24 +1626,14 @@ ext4_xattr_set(struct inode *inode, int name_index, const char *name,
handle_t *handle;
struct super_block *sb = inode->i_sb;
int error, retries = 0;
- int credits = ext4_jbd2_credits_xattr(inode);
+ int credits;

error = dquot_initialize(inode);
if (error)
return error;

- if (ext4_has_feature_ea_inode(sb)) {
- int nrblocks = (value_len + sb->s_blocksize - 1) >>
- sb->s_blocksize_bits;
-
- /* For new inode */
- credits += EXT4_SINGLEDATA_TRANS_BLOCKS(sb) + 3;
-
- /* For data blocks of EA inode */
- credits += ext4_meta_trans_blocks(inode, nrblocks, 0);
- }
-
retry:
+ credits = ext4_xattr_set_credits(inode, value_len);
handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
if (IS_ERR(handle)) {
error = PTR_ERR(handle);
diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h
index b6ef99d1a061..e82c5fe36a26 100644
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -160,6 +160,7 @@ extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
+extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len);

extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino);
extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
--
2.13.0.219.gdb65acc882-goog