ext4: avoid excessive credit estimate in ext4_tmpfile()

[ Upstream commit 35a1f12f0ca857fee1d7a04ef52cbd5f1f84de13 ]

A user with minimum journal size (1024 blocks these days) complained
about the following error triggered by generic/697 test in
ext4_tmpfile():

run fstests generic/697 at 2024-02-28 05:34:46
JBD2: vfstest wants too many credits credits:260 rsv_credits:0 max:256
EXT4-fs error (device loop0) in __ext4_new_inode:1083: error 28

Indeed the credit estimate in ext4_tmpfile() is huge.
EXT4_MAXQUOTAS_INIT_BLOCKS() is 219, then 10 credits from ext4_tmpfile()
itself and then ext4_xattr_credits_for_new_inode() adds more credits
needed for security attributes and ACLs. Now the
EXT4_MAXQUOTAS_INIT_BLOCKS() is in fact unnecessary because we've
already initialized quotas with dquot_init() shortly before and so
EXT4_MAXQUOTAS_TRANS_BLOCKS() is enough (which boils down to 3 credits).

Fixes: af51a2ac36d1 ("ext4: ->tmpfile() support")
Signed-off-by: Jan Kara <jack@suse.cz>
Tested-by: Luis Henriques <lhenriques@suse.de>
Tested-by: Disha Goel <disgoel@linux.ibm.com>
Link: https://lore.kernel.org/r/20240307115320.28949-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 05b647e6bc19547a117214b17226d97420887ce6..58fee3c6febcbd11ccdb0c3858957f8da95d7c60 100644 (file)
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2898,7 +2898,7 @@ retry:
        inode = ext4_new_inode_start_handle(idmap, dir, mode,
                                            NULL, 0, NULL,
                                            EXT4_HT_DIR,
-                       EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb) +
+                       EXT4_MAXQUOTAS_TRANS_BLOCKS(dir->i_sb) +
                          4 + EXT4_XATTR_TRANS_BLOCKS);
        handle = ext4_journal_current_handle();
        err = PTR_ERR(inode);